This Day in Weather History - August 17

August 16-17, 1985 Cold Heavy Rainfall Event with 90-140 mm

An unseasonably strong long pressure system moved into the Red River Valley from the United States August 16-17, 1985. The rain moved in late in the day on the 16th, then continued most of the 17th. There were embedded thunderstorms which produced higher rainfall rates. The system brought strong winds along with very chilly temperatures, making it feel much more like fall than summer. The rains were much unwelcomed after an already extremely wet August. Parts of southern Manitoba received over 200 mm of rain during the month from start to finish, making it the wettest on record for many. Winnipeg Airport received 218.0 mm, the wettest August on record since 1872. 

This particular storm system on August 16-17 dumped 50 to 140 mm of rain in the Red River Valley, including in the Winnipeg area. 97.4 mm of rain fell at Winnipeg Airport within a 24-hour period, a new record for the month of August, beating 84.6 mm on August 16, 1884. Some streets flooded as a result of the heavy rain, as well as over 300 basements. Two homes were struck by lightning. The axis of highest amounts was across the western Red River Valley. 

Rainfall amounts August 16-17, 1985

Portage la Prairie City 140.5 mm
Carman 139.6 mm
St Claude 127.0 mm
Portage Southport 121.8 mm
Miami 121.7 mm
Deerwood 117.6 mm
Morden 116.4 mm
Starbuck 110.8 mm
Winnipeg Airport 97.4 mm
Selkirk 95.4 mm
Stonewall 92.8 mm
MacGregor 84.0 mm

Winds gusting over 80 km/h were accompanied by the system as well. Portage la Prairie gusted to 83 km/h, Brandon 80 km/h and Winnipeg 67 km/h. The wind and rain knocked over some power lines, causing outages. Temperatures hovered around 12 to 13°C throughout the day on the 17th, making for an unusually chilly August day. The maximum of 13.8°C was a record low maximum for the date at Winnipeg Airport. 

The cold, windy and rainy weather occurred on a weekend, resulting in various event cancellations. Businesses along the shores of the lakes suffered from lack of business, which had been a theme of the summer. 

From the Winnipeg Free Press, August 18, 1985, page 1

Sources: This post contains info from the Winnipeg Free Press August 18 and 19, 1985, as well as from Environment and Climate Change Canada. 

This Day in Weather History - August 16

 August 16, 1939 Two Heavy Thunderstorms Flood Winnipeg

Two rounds of heavy thunderstorms dumped copious amounts of rain over Winnipeg on August 16, 1939. The first round of storms hit about 3 am and lasted about three hours, dumping 35.3 mm of rain at the Airport. The second storm hit about 1:30 pm, and lasted another three hours, dumping 46.7 mm. This brought the daily rainfall amount to 82.0 mm, one of the wettest days on record. 

The heavy rain flooded basements, businesses and warehouses, slowed down traffic and disrupted communications. Underpasses were under water, causing transit and motorists to take detours. The General Hospital was also flooded. The greatest damage was to downtown warehouses and businesses which stored much material in their basements. Cave-ins occurred along some roads and sidewalks. Approximately 24 schools were flooded. It was reported that hundreds of sparrows died in the storm. While seeking refuge in trees, they felled to the pavement and died. 

The City of Winnipeg proper was hardest hit. Flooded basements were also reported in St Boniface, St James and West Kildonan.  Areas to the south toward the University of Manitoba were not as hard hit, and the rain was welcomed. 

From the Winnipeg Tribune August 17 1939 page 8

From the Winnipeg Tribune August 17 1939 page 1

** Sources: This post contains info from the Winnipeg Free Press and Winnipeg Tribune, from their August 16 and 17, 1939 publications.

This Day in Weather History - August 9-10

 August 9-10, 2007 Ravaging Thunderstorms - Dauphin and Winnipeg hard hit

Severe thunderstorms, including supercells, developed over eastern Saskatchewan and western Manitoba in the afternoon and evening of August 9th, 2007. These storms moved southeastward throughout the night, pushing through Winnipeg by around 1 am on August 10th. The storms brought large hail and damaging winds across a long swath from Dauphin to Winnipeg. In Dauphin, hail up to baseball or even softball sized fell along with about 50 mm of rain and 98 km/h winds, causing extensive damage. It was one of the worst storms to ever hit the town. Almost every exposed vehicle and building suffered hail damage. Windows were smashed and roofs were destroyed. MPI received about 13,000 vehicle claims worth about 50 million dollars due to the storm. So many vehicles were damaged that there was a large boom in new car sales afterwards. 

Photos from Brandon Daily Sun August 11 2007 page 2

In Winnipeg, a wind gust of 100 km/h was recorded at the Airport. Nickel to toonie sized hail fell as well. Northern and eastern portions of the city bore the brunt of the storm. The storms across southern Manitoba caused millions of dollars in crop damage, knocked down thousands of trees and forced 7,000 customers without power. A horse near Anola was killed by powerful winds. Birds Hill Park was shut down due to the magnitude of tree damage. Sheds and fences were blown all over the place in nearby neighbourhoods. A couple golf courses were also closed due to downed trees. A City of Winnipeg forester said the storm was definitely in the top 10 worst for tree damage in the city, but not as bad as a 2005 storm. About 20-30 mm of rain fell with the storm in northern Winnipeg, while the south end received next to nothing. 

From the front page of the Winnipeg Free Press on August 11, 2007

Weather summary issued by Environment Canada

Links:

U of M page

CBC (from October 2007)

CBC (from August 2007)

CTV on television