Excessive Heat — Swift, Minnesota
2011-07-18 to 2011-07-20 · Swift, Minnesota
Event narrative
Several sources from surface observations, to local officials, media and health organizations indicated that the combination of heat and humidity, from a large dome of high pressure, allowed for excessive heat to cause significant problems for several days. Local observations around the county indicated heat index values rose above 105 degrees Monday, July 18th, and continued through Wednesday July 20th. Overnight heat index values averaged around 80 degrees with the highest heat index of 117 degrees Tuesday afternoon, July 19th. A 66 year old man in Benson collapsed when mowing his lawn, and later died at the local hospital.
Wider weather episode
A large ridge of high pressure expanded across the Upper Midwest and allowed for a stagnant pattern, and eventually oppressive heat and humidity to develop.
The heat wave broke records for temperature and dew point, and even heat indices across the region. Maximum heat index values of 115 to 125 were common.
Impacts across the Twin Cities Metro Area:
A record high minimum temperature was set on July 18th, when a low temperature of 80 degrees was recorded at Minneapolis - St. Paul International Airport. The previous record was 78 degrees which was set in 1986.
A record high minimum temperature was also set on July 20th, when a low temperature of 80 degrees was recorded. The previous record was 76 degrees which was set in 1901, 1935 and 1940.
The record high minimum temperature was tied on July 17th, with a low temperature of 79 degrees. The record was previously set in 1936 and 1942.
A heat index value of 119 degrees was calculated from a temperature of 95 and dew point of 82 at the airport at 4PM on July 19th. The dew point of 82 degrees set an all-time record at Minneapolis-St Paul airport.
In St. Cloud, Minnesota:
The second longest consecutive stretch of low temperatures at or above 70 degrees was set this week. Five days in a row, temperatures bottomed out at or above 70 degrees, ending July 20th (the longest streak in St. Cloud is 10 consecutive days, set between July 16th and July 25th 1981).
Precipitable water values during the warm and humid stretch appears to be broken with a record PWAT measurement for the period of record (1948-present) during the 6 am balloon launch on July 18th. The PWAT measured on that morning was 2.44 inches.
A total of 44 fans were treated at Target Field (32 treated in their first aid facilities and more than a dozen treated in their seats).
The heatwave led to record power demand. Xcel Energy set a new record with the highest one-day peak demand ever of a little more than 9,500 megawatts on Monday, July 18th.
The heat affected turkeys in southwest Minnesota, where 50,000 turkeys died due to heat related causes near Redwood Falls. In addition to the turkeys that died, several news articles had references to heat related deaths to livestock in southern and western Minnesota, but the articles were not specific for counties.
The heat and humidity were also blamed for road buckling on I-94 in Minneapolis.
Two lanes of northbound I-94 at Lowry Ave, and two lanes of eastbound I-94 at 49th Ave, were closed because of buckling pavement.
A 66 year old man died in Benson (Swift County) on July 20. He was mowing the lawn when he collapsed and died that day at the local hospital.
Source: NOAA Storm Events Database, event_id 336008. Narrative written by the NWS forecast office that issued the report.