A Perspective on this Cold February

A Perspective on this Cold February:

Since the record warm February of 1998 (over 14°F above normal on a statewide basis) we have seen 8 remarkably warm Februarys and 8 remarkably cold Februarys, including last year. There have been 6 others within a degree or two of normal. This February is tracking from 4 to 8°F cooler than normal around the state so far and will likely end up being several degrees colder than normal as well by the end of the month.

Although it has generally been colder than normal this month with a number of Wind Chill Advisories issued by the National Weather Service, extreme or record-breaking cold temperatures have been rare. Within the state climate network only one cold daily maximum temperature record has been set (-17°F at Litchfield on February 3rd) and only three cold daily minimum temperature records have been set (including -42°F at International Falls on February 3rd). Last February (2021) the cold temperatures were more extreme with 196 daily record cold minimum temperature records set within the state climate network, and 385 daily record cold maximum temperature records set. Valentine’s day of last year was probably the coldest in state history with many climate stations reporting morning lows of -40°F or colder and even some daytime high temperatures that were between -10°F and -16°F.

Looking out on the horizon with the medium range forecast models it is difficult to see consistent moderation in temperature until we get past the first few days of March. By then many soil frost depths will likely be between 24 and 32 inches.

A Look at Trends in Extreme Cold in Minnesota

Earlier this week I spoke with MPR Chief Meteorologist Paul Huttner about extreme cold temperatures in Minnesota. One of the topics was centered around whether or not there are any trends in extreme cold temperature measurements over the past century. Here are some statistical findings based on researching the state climate data base from 1891 when the National Weather Service climate network was formed:

*From 1891-1990 there were only 13 years (13 percent of all years) when a temperature of -40° F or colder was not observed in the state. Conversely, since 1991 there have been 9 such years (28 percent of all years), and in 2002 the coldest temperature in the state was not even minus 30 degrees F (it was -28°F at Tower on March 2, and at Warroad on March 3).

*From 1891 to 1983 there were 29 years when the extreme cold temperature measured in Minnesota was -50°F or colder (32 percent of all years). Conversely since 1983 there have only been 7 years that have brought such a temperature to Minnesota (18 percent of all years).

*Based on a survey of the climate stations within the state that have reported the absolute coldest minimum temperature reading for a year, here is a list of those with the highest frequency for such reports:
Tower (St Louis County) 18 years
Pokegama Dam (Itasca County) 13 years
Big Falls (Koochiching County) 10 years
Itasca State Park (Clearwater County) 8 years
Embarrass (St Louis County) 9 years
Cotton (St Louis County) 7 years
Warroad (Roseau County) 7 years
Red Lake Falls (Red Lake County) 6 years
Baudette (Lake of the Woods County) 6 years
Thorhult (Beltrami County) 5 years

For comparison, International Falls, known as “the nation’s Ice Box) has only reported the coldest daily minimum temperature for a year 4 times in 132 years of state climate records.

Weekly Weather Potpourri:

The United Kingdom Met Office and BBC were issuing warnings about Storm Eunice for this Friday and Saturday as it was expected to pass over areas of southwestern and central coastal regions (including Wales) with very strong winds (up to 90 mph). A wind gust of 122 mph was measured on the Isle of Wight on Friday. Large waves, rains, and even snowfall were expected as well. Many residents were warned to stay indoors and not travel by car. The storm is one of the most powerful in history.

For early next week Madagascar is in the bullseye of yet another Tropical Cyclone (Emnati) as it grows in strength across the Southern Indian Ocean. It was expected to produce winds over 100 mph and sea wave heights of 20-30 feet before it brings rains to Madagascar over February 22-23.

NOAA in cooperation with other government agencies issued a report this week called “2022 Sea Level Rise Technical Report.” It is an update on projected sea level rise based on climate trends and climate models, and the impact on coastal regions of the USA. The report says that “sea level along the U.S. coastline is projected to rise, on average, 10 - 12 inches (0.25 - 0.30 meters) in the next 30 years (2020 - 2050), which will be as much as the rise measured over the last 100 years (1920 - 2020).” In addition, the report says that “sea level rise will vary regionally along U.S. coasts because of changes in both land and ocean height.” Further there will also be an increased risk of flooding for coastal infrastructure due to storm surges.

MPR listener question:

What is the deepest frost depth recorded in Minnesota soils during the winter?

Answer:

I cannot give you a definitive answer because of the relative scarcity of data on soil frost depths. Much of the historical data in Minnesota is derived from frost tube measurements which typically record depths to 5 feet, but not beyond. There is a report from the weather observer in Brainerd, MN during January of 1918 which gives a frost depth of 91 inches (7 ft 8 in) in a coarse sandy soil. This is the deepest I can find in the climatological records. It occurred during a winter of very little snow cover and very cold December-January temperatures (about 10 degrees below normal). There have probably been deeper frost depths that have not been measured. By the way, current frost depths around the state range from 18 to 31 inches for the most part.

Twin Cities Almanac for February 18th:

The average MSP high temperature for this date is 30 degrees F (plus or minus 12 degrees F standard deviation), while the average low is 14 degrees F (plus or minus 14 degrees F standard deviation).

MSP Local Records for February 18th:

MSP records for this date: highest daily maximum temperature of 58 degrees F in 2017; lowest daily maximum temperature of -7 degrees F in 1941; lowest daily minimum temperature of -21 degrees F in 1903; highest daily minimum temperature of 36 degrees F in 2002; record precipitation of 0.70 inches in 1961. Record snowfall is 7.0 inches also in 1961.

Average dew point for February 18th is 12°F; the maximum dew point on this date is 39°F in 1999; and the minimum dew point on this date is -29 degrees F in 1981.

All-time state records for February 18th:

The state record high temperature for this date is 66 degrees F at Pipestone (Pipestone County) in 1981. The state record low temperature for this date is -48 degrees F at Roseau (Roseau County) in 1966. The state record precipitation for this date is 1.80 inches at Black Duck (Beltrami County) in 2004. Record snowfall is 16.0 inches at Worthington (Nobles County) in 1962.

Past Weather Features:

A major winter storm brought heavy snow to portions of Minnesota over February 17-19, 1962. Southern counties were in the bullseye of the storm and reported from 8 to 20 inches of snowfall. Fortunately, the most intense portions of the storm occurred over a weekend when most children were at home.

The coldest February 18 came in 1966 as a high-pressure system descended from northern Canada and settled over the state. All observers in the state reported subzero temperature readings that morning, with -40°F or colder common across the northern third of the state. The afternoon high temperature at Angus (Polk County) only reached a reading of -25°F.

February 18, 1981 was the warmest in state history. Twenty-eight southern Minnesota counties saw afternoon temperatures of 60°F or warmer, under bright sun, no snow cover, and southerly winds. Some farmers were seen in their tractors planting small grains in the bare soil.

Outlook: 

Sunny, but cool start to the weekend with below normal temperatures on Saturday and a chance for snow flurries in the north. More clouds on Sunday, but generally warmer temperatures, especially in southern counties. Then later on Sunday snow will commence in parts of the state and last through early Tuesday, delivering some significant amounts (6-12 inches) to many areas of the state. Cooler and drier for Wednesday through Friday next week.