Monday 1 January 2024

Top 10 Weather Stories of 2023 - Winnipeg, MB

 10 - August 1 Morning Thunderstorm with Magnificent Shelf Cloud

A thunderstorm complex that developed in eastern Saskatchewan August 31 kept on trucking in the night through the Interlake and eventually southeastern Manitoba by morning. The storm complex hit Winnipeg just in time for the morning rush around 8 am. 

The main story with the storm complex was the stunning shelf cloud that raced through as the storm moved in. As the shelf cloud moved through Winnipeg, it plunged the city into darkness and brought gusty winds which blew some dust around. It also exhibited magnificent blue-green colours. As the storm moved through, frequent lightning and a torrential downpour swept through. Hail fell but was only up to dime sized. The torrential rain was enough to flood some streets. Some parts of the city received about 20 mm of rain in only 20 minutes.  Central, eastern, and southeastern parts of Winnipeg received the highest reported rainfall from the storms with 20 to 30 mm. Other areas only received 5 to 20 mm. 

9 - Coldest July Since 2009 a Result of Chilly Nights

Extreme warmth in June reversed to cooler than normal weather in July. Nighttime temperatures were the coldest relative to normal and this was in large part due to lower-than-normal humidity. The average daily low temperature of 10.9°C was tied 11th coldest on record since 1872 and was 2.3°C below normal. 12 days dipped into the single digits, tied 8th most since 1873. This made the month feel more like early fall, especially after a hot June. The month overall was 15th coldest on record with a mean temperature of 17.9°C. This also made it the coldest July since 2009. These conditions were, in fact, welcomed by some residents, because it made for a much more comfortable July than usual. It was even cool enough for the development of lake-effect showers on the 16th. 

On the 11th, some patchy frost was recorded in southwestern Manitoba. Baldur dipped to 0.0°C. There were several lows around 1°C. 

The reduction in summer heat continued somewhat in August. It was the second consecutive August without reaching 30°C, a streak which had not occurred since the 1903 to 1905 period. However, August overall was around normal. It was mostly an absence of the very hot days we usually see in mid-summer. 

8 - 11 Consecutive Drier Than Normal Months

In sharp contrast to last year, which was the wettest year on record, 2023 was largely dry not only in Winnipeg but across southern Manitoba. It was not nearly as dry as the 2017 to 2021 drought, but this was mostly a result of regular thunderstorms in the summer and leftover moisture from last year and a delayed spring melt. It did not really feel like a dry year as a result, given the muted impacts. The main impact was on Manitoba Hydro, which reported a larger deficit than forecast, partly because of lower water levels leading to lesser electricity generation. Some burn bans were put in place by some municipalities in the late spring.

The driest conditions were in the winter and the spring. Winnipeg Airport had its driest January to May period on record, as shown in the table below. The precipitation amounts in the table are raw data (not quality controlled). My quality-controlled amount for 2023 is 54.5 mm (adjusted for snowfall under catch at the Airport), which would still be the driest. This was essentially a complete flip from last year which had the 2nd wettest January to May period.

The overall dry pattern did not fully break until October when the Winnipeg Airport recorded its first wetter than normal month since October of last year. With 11 consecutive drier than normal months, it was tied 2nd longest streak on record since 1872. It tied with October 2017 to August 2018. Here are some statistics from the dry spell:

  • 19th driest January
  • 12th driest February
  • 14th driest winter
  • 5th driest March (3.4 mm)
  • 7th driest spring and 12th least rainy (about 1/3 of normal precipitation)
  • 18th driest May
  • 8th driest December
  • 9th driest year on record with about 373 mm of precipitation, 142 mm below normal. 

7 - 4th Hottest September Day Highlights 5th Warmest September

It was another warm September in Winnipeg. With a mean temperature of 16.2°C, it was the 5th warmest September on record and the warmest since 2009. Overnight lows were most abnormally warm, averaging 9.9°C, the 2nd warmest on record.

The hottest weather was the in the first three days of the month during the Labour Day long weekend when temperatures soared above 30°C. On the 2nd, temperatures exceeded 35°C in the Red River Valley, making it one of the hottest September days in years. Winnipeg Airport reached 36.6°C, the 4th hottest September day on record. 

The coldest day of September had a high temperature of 15.4°C. This was the highest on record since 1872. The lowest temperature of the month was 1.5°C, the 9th highest. 

6 - March Without a Thaw Highlights Cold Start to Spring

It wasn`t a particularly harsh winter like the previous winter, but it was just as prolonged. We can almost always count on thawing weather conditions in March, but 2023 was an exception. Not a single day exceeded the freezing mark at Winnipeg Airport in March, only the second time that that has occurred in Winnipeg since 1872. The other time was in 1899. The highest the Airport got in March was -0.8°C, the second lowest monthly maximum since 1872. This was about eleven degrees below the normal maximum of 10°C. Note that areas around downtown did see a few thaws thanks to the urban heat island. The Forks reached a monthly maximum of 1.7°C. 

Overall, it wasn’t a particularly cold March, however, only tied 34th coldest on record. This was the coldest since 2014 and about five degrees below normal. It was consistently moderately below normal. 27 days dipped below -10°C, the most since 1970. Some would even say it was a pleasant March because of abundant sunshine and generally quiet weather. There was only about 3 mm of precipitation, the 5th driest on record. Not a single drop of liquid precipitation fell (drizzle or rain). The last time this happened was in 1956. 

Model reanalysis product showing temperature anomaly for the month of March.

Winnipeg was lucky, however, as a strong storm system brought a blizzard to southwestern Manitoba on March 11 and dropped 10 to 20 cm of snow along the US border. Winnipeg only received about 6 cm, the only day with any substantial precipitation in March. This, along with a very snowy winter, and more snow April 4-5 and April 19-21, produced an extensive and deep snowpack across southern Saskatchewan into North Dakota, making it very difficult to warm up. This extensive snowpack was certainly a factor delaying the arrival of spring in southern Manitoba as it acted like a localized freezer preventing warm air from advancing northeastward. 

The snowpack in parts of North Dakota did not fully melt until late April. Fargo had its 6th longest period with snow depth over 2 cm with 148 days. The effects of this snowpack were most evidenced on April 11 when very warm air aloft moved over the region. Snow-free areas of western North Dakota reached 30°C, while snow covered portions of eastern North Dakota only reached up to 7°C. Winnipeg reached the low teens, while forested areas in the Whiteshell reached as high as 20°C. 

It was the 11th coldest March in Fargo, 6th coldest in Bismarck and 4th coldest in Grand Forks (according to Daryl Ritchison).

March 20 in St Norbert

The chilly weather continued into April, before the weather pattern flipped to warmer than normal weather in early May. It was the 31st coldest April. The first 5°C of the year was April 8, tied 8th latest. The monthly maximum in April was 14.3°C, the 9th lowest. 

The spring was so delayed that outdoor skating rinks were still in use in the first week of April. The maple syrup season was severely delayed as well. Snowmobilers were happy. 

5 - Warm and Smoky Year with a Long Growing Season

After a colder than normal year last year, warm weather returned in 2023. With a mean temperature of 4.2°C, it was tied 11th warmest year since 1872 with 2015. Fall was the most anomalously warm season. Fall was tied 13th warmest since 1872, and 8th warmest for daily low temperatures. 

Thanks to warm weather late in the spring and early fall, we had one of the longest growing seasons ever recorded. At Winnipeg Airport, temperatures remained above freezing from May 5 to Oct 7, a total of 156 days, the 2nd longest growing season at the station since 1938. Only 1963 had a longer growing season with 157 days. 

2023 also had the most consecutive days above 15°C with 139 days from May 19 to October 4. The old record was 133 days in 1987. 

Unfortunately, with the warm and dry weather that dominated western Canada and the Arctic in 2023, fire and smoke were problematic, from late spring to early fall. Although the fire season was not exceptional in Manitoba, it was record breaking out west with numerous fires in the Northwest Territories, Alberta, Saskatchewan, and British Columbia. Smoke from these fires choked skies across the Prairies on several days. In Winnipeg, much of the smoke thankfully remained aloft, giving hazy skies, but we still got our fair share of smoky surface conditions. In terms of the absolute number of hours with smoke reducing visibility at the Airport, May and June were the 3rd smokiest on record and September was the smokiest. The year as a whole saw 125 hours with smoke, the smokiest since 2021, the second smokiest since the early 1960s, and the 11th smokiest since 1953. 

Both winters were mild as well. There were notably fewer days below -20°C in 2023 than normal. Only 28 days dipped below -20°C, the fewest since 1987 and the 3rd fewest on record since 1872. Both January (7 days) and December (1 day) tied for 2nd fewest days below -20°C. 

130 days rose above 20°C in 2023, tied 7th most since 1872. Because of colder weather in March, April and November, the number of days above 10°C was slightly below normal for the year. 

4 - Wet and Humid October with Heavy Thunderstorms and a White Halloween

October finally broke the streak of dry months which began in November of 2022 at Winnipeg Airport. In fact, October was the wettest month of the year in 2023, only the second time on record that that has happened. 1949 was the only other year where October was the wettest month of the year. About 79 mm of precipitation fell at the Airport, the 10th wettest on record since 1872. 65.4 mm of this was rain, making it the 14th rainiest October. 

Most of the rain fell in the first week of October when a wave of warm and very humid weather moved into southern, and especially southeastern Manitoba. Southern Manitoba was, in fact, in the battle zone of air masses with temperatures over 30°C in southeastern Manitoba and below 20°C in southwestern Manitoba because of a nearly stationary front. On the 1st, highs of 31.0°C in Menisino, 30.4°C in Emerson and 30.0°C in Sprague were recorded. Sprague then reached 28.1°C and 27.4°C the following two days. 

High humidity sent dewpoints to incredible values above 20c in southeastern Manitoba as well. The heat and humidity combined resulted in humidex values in the mid to high thirties. The highest calculated humidex was 38 in St Pierre and Menisino. Usually, hot weather in October is dry in southern Manitoba. This combination of heat and humidity was very rare as a result. Winnipeg Airport (CXWG) reached a dewpoint of 18.8°C on the 3rd, a new record for the month of October, beating 18.6°C in 1997. In fact, daily dewpoint records were broken three days in a row, both the 1st and 3rd seeing values over 18°C. 

Several waves of thunderstorms moved through southern Manitoba in the first few days of October, aided by anomalously high humidity for that time of year. The most notable event was in the early morning hours of October 3rd when a large complex of thunderstorms moved through the Red River Valley. Although thunderstorms are still relatively common in October, they are usually not intense. These storms were of July standards, quite rare for October. For Winnipeg, it was potentially the most intense thunderstorms in October since 1955. 

Radar image at 7:29am on Oct 3, via Radarscope

The squall line that moved through Winnipeg just after 7 am on October 3rd plunged the city into darkness and produced nearly constant lightning flashes and intense thunder. Rain was very heavy, especially by October standards, and was enough to cause street flooding. The storms lasted about 4 hours. At Winnipeg Airport, a new rainfall rate record for October was broken. 16.0 mm of rain fell in 60 minutes, breaking the previous record of 10.8 mm in an hour in 1984. 14.8 mm in 30 minutes, exactly doubling the previous record of 7.4 mm in 1968. Even more impressive were the tripling of the 5-min, 10-min and 15-min rainfall rate records. 

Note that these rainfall rate records are specific to the Airport. A heavy thunderstorm event on October 5, 1955 might have been heavier or similarly heavy around downtown, but rainfall rate records were not available there at the time. The storms on that date had lasted about 5 hours and dumped up to 55 mm in St Boniface. 

Infrared satellite image from Oct 3 showing the storm complex over Winnipeg

Environment Canada map showing lightning strikes on Oct 3

36.2 mm of rain fell in total on October 3 at the Winnipeg Airport, a new daily record, beating 29.2 mm in 1911. Some private stations in western Winnipeg received up to 40 mm. Locally, 40 to 50 mm of rain fell north and northeast of the city. 

Just two days later, another low-pressure system brought 20 to 30 mm of rain in the morning. The lakes were so warm that the cooler air moving over them produced lake-effect thunderstorms west and east of Winnipeg, something that is rarely seen in these parts. 

There was also another bout of thunderstorms on October 1st, which affected mostly western Manitoba through eastern Manitoba. During the late evening, ping pong ball sized hail fell in Oakburn, causing damage to vehicles. 

Colder weather did finally arrive in the last week of October. Frequent systems brought bouts of snowfall which left southern Manitoba looking like late November. Winnipeg had its first white Halloween since 2006 with about 7 cm on the ground. It was also a cold Halloween with morning temperatures of -12°C and a high of only -4°C. Parts of southwestern Manitoba and western North Dakota dipped below -20°C. 

In total, 21.6 cm of snow fell in Winnipeg in the last seven days of the month, making it the 11th snowiest October since 1872 and snowiest since 2019. From the 25th of October, snow remained on the ground for about two weeks. The biggest storm was on the 27th when 12 cm fell. Other days ranged from a dusting to 3 cm of new snowfall. Higher snowfall amounts fell in intense snow squalls downwind of the lakes west and east of the city, especially on the 30th when locally 20 cm fell around Tyndall and Anola, and the 28th when close to 20 cm fell around Woodlands (Cocorahs report). Berens River had over 30 cm. 

Halloween morning in Winnipeg

3 - Strong El Nino Brings Very Mild and Dry December

The return of a strong El Nino in the fall and winter helped to delay the arrival of ‘‘permanent’’ winter conditions. The cold snowy weather of late October provided concern that a very early winter was in store, but mild weather in November and early December continually melted any snow that had fallen. As a result, November and early December were very pleasant with mild weather and mostly snow-free ground. 

No snow on the ground at Winnipeg Airport on Dec 7

The ground was completely snow-free in Winnipeg, and most of southern Manitoba, as late as the morning of December 8, allowing golf courses to reopen for rare December golf. A snowstorm beginning in the afternoon on the 8th created a snow cover that did not fully melt the remainder of the month in most, but not all, of southern Manitoba. 

Temperatures reached double digits on the 6th and 7th in parts of southern Manitoba. Winnipeg got close with a record high of 8.6°C on the 7th. This broke the old daily record of 5.6°C in 1923. It was the 8th warmest December day since 1872 and the warmest since 1998. It also reached 6.9°C on the 6th. Downslope areas along the escarpment and the Riding and Turtle Mountains reached almost 13°C locally. 

It was even warmer in North Dakota where temperatures reached the high teens. Fargo had its 2nd warmest December day on record on the 7th with a high of 16.7°C, shattering its daily record of 11.7°C in 1939. Grand Forks reached 12.8°C. Some parts of southwestern North Dakota reached 18°C on the 6th. Parts of southern Saskatchewan were also warmer, with highs up to 16°C in Maple Creek. Calgary reached 17.0°C. 

On the 14th, Thunder Bay reached a new all-time December high of 13.7°C. 

There was much chatter throughout the month about the potential of a brown Christmas in Winnipeg, but in the end, it did not materialize. The ground was white on Christmas morning as it is almost every single year, but the snow was noticeably thinner than in recent years with only 2 cm on the ground, the thinnest since 2011. 

Some parts of southern Manitoba did see a brown Christmas, such as in western parts of the Red River Valley and in the southern Interlake. These snow-free areas were continually warmer than areas with snow. On December 27, it once again reached over 5°C in some areas, while Winnipeg only reached 0.7°C. McCreary reached 10.4°C, while Pipelake (northwest of Dauphin) reached 9.8°C, Winkler 8.5°C, and Eden (northeast of Minnedosa) 9.3°C. Winkler (Mb Ag station) apparently reached 10.7°C on the 28th, though it seems suspiciously high. McCreary reached 9.1°C on the 28th and Ethelbert 7.8°C. 

Much of southern Saskatchewan and Alberta had a brown Christmas, including Saskatoon, Regina, and Edmonton. Thunder Bay also had a brown Christmas. 

In the days leading up to Christmas, it was very mild and foggy with periodic drizzle on the 22nd and 23rd. It felt more like the Maritimes than Manitoba. We had the rainiest Christmas Eve on record with about 1.7 mm at the Airport early in the morning. A switchover to snow in the morning sealed the deal so to speak with respect to a white Christmas. The rain and warm temperatures melted much of the snow that was on the ground beforehand, exposing some grass, before switching to snowfall. Winnipeg only reached 1°C during the warm spell because of the cloud cover. Areas that got sunshine west of the Red River Valley got warmer. The warmest spot was north of the Turtle Mountains where, on the 23rd, Deloraine reached 8.8°C, Boissevain 8.5°C and Killarney 7.4°C. 

Even heavier rain fell in southeastern Manitoba on Christmas Eve. Sprague received about 12 mm of rain. Generally, 5 to 10 mm of rain fell in a swath from Sprague-Menisino to Falcon Lake-Prawda. 

Ducks were witnessed on the Red River in Winnipeg on Christmas Eve. The river mostly froze over during the month, but some sections did not fully freeze. 

Six days had fog at Winnipeg Airport, making it one of the foggiest Decembers on record. It was the foggiest since at least the 1950s. 

December 27 satellite image showing snow cover in green.

December overall averaged -5.8°C at Winnipeg Airport, the 3rd warmest since 1872, and   7°C above normal. Only 1877 and 1997 were warmer. Daily high temperatures averaged -1.2°C, the 2nd warmest on record. 30 of 31 days were warmer than normal. The warmest areas were along the escarpment where daytime highs averaged above freezing, such as in McCreary (1.8°C), Morden (0.6°C), Deerwood (0.6°C), Portage and Carman (0.3°C). At Winnipeg Airport, 11 days exceeded the freezing mark, tied with 1890, 1939 and 2020 for 6th most on record since 1872. McCreary had 19 days above freezing and Morden had 18. 

The first -20°C of the season did not arrive until December 18, tied 6th latest since 1872 and about three weeks later than normal. Only 1 day dipped below -20°C in December, tied 2nd fewest since 1872. The monthly minimum temperature of -20.6°C was the 3rd highest. Only 1877 (-18.3°C) and 1959 (-20.0°C) had higher minimum temperatures. 

The mild start to winter was welcomed by many after the previous two winters which were long. However, winter enthusiasts were not impressed by the lack of snow. Snowmobilers and cross-country skiers would have liked more snow. In addition, sales of winter equipment were down significantly, and ski hills could not open as early as usual. 

In eastern North Dakota, there was also a severe long-duration ice storm which dumped 50 to 80 mm of rain in southeastern parts of the state from December 23 to 26, including around Fargo. Ice accumulated to over two inches, downing hundreds of power poles and causing much damage to trees. The storm left thousands without power and shut down interstates. The rain was so heavy that even some basements were reported flooded, and river levels were expected to rise to minor flood levels along the Red River. NWS Grand Forks issued their first flood warning on record (since 2003) in December in the Fargo area. The amount of rain that fell on mostly frozen ground in December was possibly unprecedented for the area. Luckily, the system completely dodged Manitoba, leaving us with mostly sunny skies and calm weather during the holidays. Fargo had its wettest December on record, with over 75 mm, thanks to the event. 

2 - Warmest May-June Period on Record

Despite a late start to spring in 2023, summer still came early, and it was one of the hottest starts to summer on record. The May-June period was tied warmest on record since 1872. 

The long stretch of warmth began on May 3rd with the first 20°C of the year, about 11 days later than normal. From then on, it remained above normal almost every day through to the start of July. The last spring frost at the Airport occurred on May 4, the earliest since 1991 and 2nd earliest since 1938 at the location. This was also three weeks earlier than normal. The green-up of plants occurred very quickly because of a very cold April followed by the sudden switch to summer. We started May with no green grass and barely any budding on trees. Only three weeks later, trees were mostly fully leaved, and grass was green by the May Long Weekend. 

In the end, May was the 2nd warmest on record since 1872, behind only 1977. 5 days reached 30.0°C, tied 4th most since 1872. All these five days occurred consecutively from the 25th to 29th, during the hottest part of the month. Parts of southern Manitoba reached over 32°C during this heat wave. 22 days reached 20.0°C, also tied 4th most. Despite all the warm weather, only one record was broken: a record high minimum temperature of 18.4°C on May 26. 

The heat continued into June. The first week of June was downright tropical in southern Manitoba. It was hot and sunny with record humidity and daily pop-up thunderstorms. In fact, there were six consecutive days with thunderstorms reported at the Airport, a first since 1953. The previous record was five consecutive days. 

It was the 2nd warmest June on record since 1872 in Winnipeg with a mean temperature of 21.0°C. It was also the most humid June on record since 1953. Thanks to the humidity, overnight lows were most abnormally warm. The average daily low of 14.6°C tied with 1988 for warmest on record in June. The lowest temperature recorded during the month was 6.8°C, the second highest on record since 1872. 

The month pretty much rewrote the record books for humidity in June. 9 days had dewpoint over 20°C, eclipsing the previous record of 6 days. 7 daily high dewpoint records and 6 daily high minimum dewpoint records were broken. The dewpoint of 22.3°C on the 5th was the earliest in the season we have had dewpoint of 22°C since 1953. 3 daily high minimum temperature records were also broken: 18.7°C on the 3rd, 20.1°C on the 4th and 20.8°C on the 20th. In total, 21 daily records were broken for dewpoint, temperature, and humidex. 

With the area of warm high pressure that dominated southern Manitoba, it was also tied the calmest June since 1953 in Winnipeg with an average hourly sustained wind of 14 km/h. Given the high-pressure area, thunderstorms that developed were slow-moving, dumping torrential downpours over localized areas. On June 3rd, the Airport recorded 53.3 mm in an hour, while some other parts of the city barely received a drop of rain. What’s unusual is that the Airport had a similar event just last year. 

June 4 satellite showing pop-up t-storms in southern MB (via College of Dupage)

The warm weather was not localized to southern Manitoba. In fact, we were just experiencing part of what was one of the warmest starts to summer ever recorded in western Canada. Large sections of the Prairies and Arctic recorded its warmest May, and June was not much different. Unfortunately, the hot weather was also accompanied by drought. This caused a record start to the fire season with numerous fires, particularly in Alberta and the Northwest Territories. Most days were choked with smoke in May and June. Southern Manitoba did receive some of this smoke, but luckily not nearly as bad as out west. Thankfully, much of the smoke remained aloft and could not be seen at the surface. In Alberta, the warm weather could not be enjoyed because of the days and days with thick smoke at the surface. At Winnipeg Airport, it was the 3rd smokiest May and 3rd smokiest June since 1953 according to the number of hours with smoke reported. There were a combined 43 hours of smoke. On average, there are only around 4 hours. Smoke is reported by the observer when it can be smelled and is causing a reduction in visibility. I personally noted that smoke could be seen aloft on at least 8 days in May, mostly between the 14th and 23rd, causing a cloudier-looking sky. 

South of the border, Fargo had its warmest June on record since 1881 and Grand Forks its 2nd warmest since 1893 (according to Daniel Riddle from NWS Grand Forks). 

A large swath of western Canada had its warmest May since 1940, according to the ERA5. Posted on Twitter (X) by Brian Brettschneider.

1 - Year of Hailstorms

2023 was one of the most damaging and costly years on record in the province for hail claims. Numerous hailstorms struck the province, including around the Winnipeg area where at least four significant hailstorms caused damage. Almost 12,000 hail claims were made to MPI for the year up to early September. The worst storm was on August 24, when large hail combined with damaging winds in northeastern Winnipeg. This storm alone accounted for about a third of the year’s hail claims. On July 26, a supercell which blew up north of Winnipeg dumped baseball sized hail in the Selkirk area. On May 10, loonie sized hail fell in Winnipeg. Each event is summarized below.

May 10 Severe Thunderstorms

An upper-level wave moving through southern Manitoba kicked off the season's first severe thunderstorm outbreak. Instability and wind shear worked perfectly together to form well-organised thunderstorms with large hail, gusty winds, and torrential downpours. Although it isn't unheard of to see severe weather that early in the season, it was a little unusual to see as much hail as was witnessed. Pretty much every single thunderstorm that developed produced hail, and often as large as quarters and loonies. A few isolated stronger storms dropped hail as large as ping pong balls or even golf balls. Winnipeg was hit by at least two severe thunderstorms with hail up to loonie sized. The first storm moved along Portage Avenue from Headingley to downtown. The second hailstorm moved through the southern portion of the city. There was some minor damage to plants and vehicles, and apparently two dealerships in the St James area had damage.

St James Winnipeg. Elisha Dacey/Twitter
Golf ball sized hail at Hallboro (south of Neepawa). By Lorri Pederson on Facebook

One storm even exhibited super cellular characteristics in southwestern Manitoba. Tornado warnings were issued. A funnel cloud was observed near Hamiota, with no evidence of a touchdown.

The storms dropped highly variable amounts of rain, ranging from 1 to 45 mm. Ste Rose du Lac suffered significant street flooding from the heavy downpours. In Winnipeg, amounts ranged from a few mm to over 20 mm. Localized wind gusts over 80 km/h were observed, particularly in the Interlake and southeastern Manitoba. The maximum gust recorded was 87 km/h in Petersfield. 

More info and pictures from the event at this link

Visible Satellite showing the tornado-warned storm in SW Mb and the ice-covered lakes (Tom Stef on Twitter)

July 25 Thunderstorms Make for Sleepless Night

It was a noisy night in the Red River Valley on July 25 as training elevated thunderstorms from the northwest brought several hours of thunderstorms. In Winnipeg, thunderstorms began after 11pm on the 24th and continued right through to mid morning. That's over 8 hours of thunderstorms. With that amount of rain and thunder, it was difficult to sleep. 

The thunderstorms were mostly heavy rain and prolific lightning producers, but some stronger cells did produce large hail and gusty winds. Southwestern portions of Winnipeg received the brunt of the more intense cells, with reports of hail as large as 3 cm in diameter. Rainfall amounts of 50 to 70 mm also fell along a stretch from Charleswood southeastward to St Norbert. Eastern parts of the city only received as little as 10 to 20 mm. The highest rainfall amounts were mostly along a narrow swath from Woodlands through southwestern Winnipeg, southeastward to Sundown in southeastern Manitoba. 

The swath of large hail also passed southeast of Winnipeg, affecting the St Pierre, Rosa and Otterburne areas. Hail up to about nickel sized also caused some damage to vehicles and gardens in Portage la Prairie. Zhoda recorded a wind gust of 100 km/h and 45 mm of rain in an hour at the Manitoba Agriculture station. 

Charleswood, Winnipeg, by Barbara Kauk on Facebook

July 26 Supercells Dump Baseball Sized Hail North of Winnipeg

Very hot and humid weather culminated in explosive discrete supercell thunderstorms in the Interlake and southeastern Manitoba late in the day on July 26. Dewpoint temperatures reached as high as 26°C in the Red River Valley along with temperatures between 30 and 35°C. This provided ample instability for explosive thunderstorms. A passing cold front with much drier, but still hot air, provided the trigger. 

The storm that produced the largest hail reports was near Fisher River First Nation in the Interlake where hail up to 10 cm in diameter fell. The storm also produced a tornado north of Riverton. 

Near Fisher Bay. By Michael Nowak on Twitter

A supercell thunderstorm also developed just north of Winnipeg and moved east southeastward. It dropped golf-ball sized hail around Selkirk and southeastwards to Falcon Lake. Localized reports of baseball sized hail were also received (7 cm diameter). A tornado warning was issued, but no tornadoes were reported. 

As can be imagined with such large hail, damage was substantial. Some of the damages included smashed windshields, damaged siding and even cracked metal roofs. In the Whiteshell, campgrounds were badly damaged, including trailers and tents. 

Although hail was the main story with the storms, localized damaging wind gusts in downbursts occurred as well. Beausejour was particularly hard hit by the wind gusts, making people believe a tornado went through. Investigation showed it was a downburst. The wind was enough to rip shingles off some buildings, rip off siding and down some trees and power poles

Ominous-looking wall cloud west of St Andrews

August 24 Hailstorm in Northeastern Winnipeg

A weak trough or cold front moving through southern Manitoba sparked off several severe thunderstorms with damaging hail and winds in the afternoon and evening of August 24, 2023. It had been a warm and humid afternoon with highs in the high twenties along with dewpoints around 20°C. In the morning, it was mostly cloudy with fog patches after some light rain the day before. Skies cleared out by the late morning or early afternoon, making way for thunderstorm development.

Severe thunderstorms initially developed around the Riding and Turtle Mountains and pushed eastward. More severe storms developed in the Red River Valley and Interlake by late afternoon and evening.

Radar showing the supercell over NE Winnipeg (Radarscope)

Visible satellite showing the storm over NE Winnipeg (College of Dupage)

One severe storm formed just northwest of Winnipeg Airport and moved through the northern and northeastern portions of the city. It moved through Amber Trails, Garden City, the Kildonans, Transcona and Dugald east of the city. It was one of the worst storms to strike the city in years, dropping immense amounts of large hail ranging from nickel to golf ball sized. Damaging winds and torrential downpours accompanied the hail, causing widespread and significant damage and near-zero visibility during the storm. A wind gust of 133 km/h was recorded at Dugald by Manitoba Agriculture. Trees were uprooted and large branches were knocked down, causing damage to vehicles and buildings. Windows in buildings and cars were smashed or dented. One dealership alone in eastern Winnipeg reported more than 200 cars damaged. The hail caused holes in siding and gazebos. Gardens were flattened and fences knocked down. Some street signs were snapped, and a semi truck was knocked over by the wind. There was so much hail that it had remained on the ground for at least 3 hours after the storm. Patchy hail fog was also witnessed. It was reported that about 10,000 people lost power during the storms, and a few thousand still were without power the following morning. 

The storm caused significant wind damage, uprooting and knocking down trees

The storms also dropped golf-ball sized hail in Alonsa. Additional storms pushed through the Interlake and eastern Manitoba through the overnight hours, dropping more large hail in spots. Wind gusts of 89 km/h in Oak Point and 88 km/h in Inwood were also recorded. Rainfall amounts were generally not very impressive. The Winnipeg storm dropped between 15 and 25 mm, enough to cause some localized street flooding. Some fields were under water as well. Unofficial rainfall amounts of 100 mm were recorded in the Selkirk area, where there was significant street flooding reported. A private Weather Underground station in Tyndall recorded about 46 mm. One farmer near Selkirk reported a total loss to his canola field due to hail.

In Winnipeg, the storm was localized. No rain fell in southern and western parts. 

More info and photos at this link

Photos from the storm in Winnipeg (except knocked over semi truck is east of Winnipeg)

Hail fog at Kildonan Park

This post contains information retrieved or derived from a variety of sources (some of which are linked in the post):
CBC, Twitter, Facebook, ECCC, Brandon Sun, Cocorahs, Manitoba Agriculture, City of Winnipeg, Weather Underground, CTV, Global News, Radarscope, NOAA, College of Dupage, NDAWN (Daryl Ritchison), Valley News Live, Grand Forks Herald, Inforum, Steinbach Online. 

Wednesday 18 October 2023

This Day in Weather History - October 18-19

 October 18-19, 1920 Unseasonably Strong Thunderstorms in Southwestern Manitoba

Thunderstorms moved through southwestern Manitoba and the Interlake from the evening of October 18 to the morning of October 19, 1920. They were part of a larger system which also struck Alberta and Saskatchewan with a snowstorm. The thunderstorms were unusually strong for that late in the season, causing minor wind damage and locally 20 to 40 mm of rain. Large hail was also reported in some areas such as Rapid City. It appears a southwest to northeast swath from Souris to Minnedosa to Eriksdale experienced the worst of the thunderstorms. The snowstorm struck hardest between Medicine Hat and Swift Current, and snow fell as far east as Biggar, SK. 

A summary of the storms by location as follows:

Brandon - Rainfall during the electrical storm totalled 13.7 mm. Very little damage in Brandon. Some fuses were burned out at the Telephone and Telegraph offices, but were back to normal by morning. 

Souris - The storm seemed to break in all its fury and some property damage resulted. Some telephone wires were down. 

Minnedosa - An electrical storm of midsummer violence, even worse than any experienced this past summer. The first storm struck about 10:30 pm on the 18th, and another storm at 10 am the 19th. A farm house was struck by lightning and completely destroyed. The power plant was put out of commission. Several wires were blown down. 

Burrows (possibly near Grandview) - A thunderstorm with heavy rain passed over this district early in the morning on the 19th. 

Glenboro - A heavy rainstorm with severe thunder and lightning struck the town the night of the 18th-19th. It lasted for an hour or so. 

Rapid City - One of the most unseasonable storms in the recollection of the oldest inhabitants. Commencing the evening of the 18th, there was a little rain with thunder and lightning, which increased during the night into a regular mid-summer storm and almost died away again in the morning only to return with increased severity about 9 am. In town, the streets were almost white with large hail stones and the downpour was the largest this year. There was thunder and lightning intermittently for about 16 hours. 

Rivers - The heaviest storm of thunder and lightning of the season passed over this district the night of the 18th-19th, accompanied by a deluge of rain. A number of phones were put out of commission, but otherwise there was no serious damage. 

Russell area - A heavy electrical storm in the evening of the 18th, accompanied by heavy rain. The lightning was very vivid and severe. Four horses were killed by lightning south of town. 

Mulvilhill (between Ashern and Eriskdale) - A farm home was burned to the ground during a severe electrical storm which passed over after 5 am on the 19th. No one was home at the time. 

Churchbridge SK - A rig in which 4 children were driving to school was struck by lightning. One girl died from its effects and another badly burned. 

Rainfall amounts from the storms as follows:

Rapid City Forrest 43.2 mm
Minnedosa 33.8 mm
Hillview 23.6 mm
Souris 15.2 mm
Brandon CDA 13.7 mm
Virden 12.7 mm
Dauphin 12.2 mm
Swan Lake 11.2 mm

From the Winnipeg Tribune Oct 20 1920 page 1

From the Rapid City Reporter OCc 21 1920 page 4

This post contains information from the Winnipeg Tribune, Winnipeg Free Press, Birtle Eye Witness, Brandon Daily Sun, Dauphin Herald, Glenboro Gazette, Rapid City Reporter, Rivers Gazette, Russell Banner and ECCC. 

Sunday 15 October 2023

This Day in Weather History - October 15

 October 15, 1952 Blast of Winter with Damaging Winds over 110 km/h

A vicious cold front moved through the Red River Valley early in the morning on October 15, 1952, bringing sub-freezing temperatures, snow and damaging winds. 

In Winnipeg, snow began to fall as early as midnight, but really began to come down with strong winds by 5:30 am. It continued until 8 am. 2.0 cm fell. Winds strengthened during the overnight, reaching their peak around 6:30 am. At that time, winds were sustained near 72 km/h and gusting up to 114 km/h. The snow, combined with strong winds, produced visibilities as low as half a mile (800 metres) at 7:30 am at the Airport. Conditions were reportedly locally worse outside the city. Temperatures fell to -4.4°C by 8:30 am and remained below freezing the remainder of the day. The afternoon high was a measly -1.7°C, a record low maximum for the day and one of the coldest days for so early in the season on record. 

Sub-freezing temperatures, strong winds and snowfall resulted in treacherous driving conditions. The morning commute was chaotic in Winnipeg. The city tried sanding some routes to increase traction. It was said that some people were up to an hour late for work because of traffic tie-ups. Some power outages occurred after the wind snapped some power lines and blew fuses. The wind also knocked down tree branches. The weather had calmed down by 10 am. 

Heavier snowfall amounts fell with the storm in other parts of southern Manitoba, particularly in the Interlake and Parklands where 10 to 20 cm was recorded:

Moosehorn 22.9 cm
Arborg 15.2 cm
Dauphin 10.7 cm
Great Falls 7.6 cm
Indian Bay 5.1 cm
Deerwood 3.8 cm
Sprague 3.8 cm
Plumas 3.3 cm
Boissevain 1.3 cm
Gimli Airport  Trace
Emerson  Trace
Brandon  Trace

The following night was cold with a low of -10.0°C at Winnipeg Airport. Other lows included:

Moosehorn -18.3°C
Sprague -15.0°C  (-16.7°C a night later)
Gimli Airport -13.9°C
Deerwood -13.3°C
Emerson -13.3°C
Morden -13.3°C
Pilot Mound -12.8°C
Indian Bay -12.8°C
Altona -11.7°C
Cypress River -11.1°C
Boissevain -10.6°C
Brandon CDA -10.6°C
Brandon Airport -10.0°C

From the Winnipeg Free Press Oct 15, page 1

From the Winnipeg Free Press Oct 15, page 4

From the Winnipeg Free Press Oct 15, 1952, page 3

This post contains info from the Winnipeg Free Press, Winnipeg Tribune and Environment and Climate Change Canada.