February 2011 and Winter 2010-2011 St. Cloud Weather Summary

Judging from complaints I've heard, this winter has seemed like it has gone on forever and has been continuously brutal. However, except for snowfall and snow on the ground, the official St. Cloud statistics do not bear out that it has been a brutal winter.

Note: This is a summary of meteorological winter, which is defined as the three coldest months of the year (1 December through 28 February). Astronomical winter ends on thespring equinox, which will be on March 20 this year. That's the day when we get back to 12 hours of daylight. Also, note that the cold season can be used to refer to the part of the year when Minnesota can get snow (typically Nov-Apr, but can be longer) or the heating season (July 1-June 30).

4th Snowiest, Wettest Winter

Although the snow season got off to a slow start, snow was plentiful throughout the winter months. Between December 1, 2010, and February 28, 2011, a total of 47.6 inches of snow was recorded at the St. Cloud Reformatory. That was more than eighteen and a half inches more than the average three-month total and ranks as the 4th snowiest winter season out of 105 winters in St. Cloud recorded history. It was the snowiest winter season since 1985-1986.

February finished this snowy winter with another 10.9 inches of snowfall, 3.7 inches more than normal. Unlike earlier months, February saw less frequent snow (measurable snowfall on only 8 days of the month, compared to 12 in December and 16 in January). However, 8.5 of the 10.9 inches fell during the storm of February 20-21, which produced 20 inches in Madison and 10-19 inches in the Twin Cities. While this was the biggest snowfall to hit St. Cloud this season, it was yet another snow storm whose brunt missed St. Cloud.

For the season, St. Cloud has had 40 days this cold season with measurable snowfall (8 in February), the most since 2003-2004 and the second highest number of days during the past 15 years, but only 1 day so far with 5 inches in a day.

That meant that all three winter months (December, January, and February) had at least 10 inches of snow. This has only happened five other times in St. Cloud records, most recently in 1985-1986. The bad news? All five of those years had one more month with at least 10 inches of snow (either November or March), so those years would indicate we may be due for a snowy March. On the other hand, only two of those five years ended up having one of the top 10 cold season snowfalls, most notably the 1936-1937 season which ended up the 2nd snowiest cold season on record.

It might stand to reason that those seasons with lots of winter snow would tend to be cold ones, because the snow cover has such a dramatic effect on cooling. It reflects the sun's energy back to space during the day and is very efficient at radiating heat out to space at night. In fact, the 2010-2011 winter snowfall seems to be most similar to 1978-1979, but that year's average winter temperature was far colder. On the other hand, the highest snowfall season of 1936-1937 was the warmest, indicating that the air has to be warm enough for sufficient moisture to produce major snowstorms. This is one reason why the predictions of global warming include more precipitation at higher latitudes, consistent with the winters over the past few years, especially in the Red River Valley.

The snowfall contained quite a bit of liquid, with 6-10 inches of water locked up in the snowpack in western and southwestern Minnesota into the eastern Dakotas. However, don't forget that December was the wettest December in St. Cloud records, partly due to a late December storm that produced over 0.8 inch of rain. The combination pushed the winter precipitation to 4.41 inches, also the 4th wettest winter (Dec.-Feb.) in St. Cloud records and the wettest since the 1968-1969 season. February contributed to that wetness with 0.88 inch, about a quarter inch more than normal.

For the snow season so far, which began with our snowfall on November 13, there has been a total of 51.2 inches through the end of February, a shade more than 15 inches above normal. That's the highest snowfall total through the end of February since 1993-1994 (54.2 inches). That cold season ended up with 64.9 inches of snow. How much snow have we missed? Through the end of February, Minneapolis-St. Paul International Airport has had 74.8 inches of snow, 23 more inches than St. Cloud (and the 10th highest total on record).

Also notable about the snow season so far is the long period that the snow has been on the ground. We've been staring at the snow pack since November 23, which makes 97 consecutive days with at least an inch of snow on the ground. On the average, St. Cloud's period of continuous snow cover lasts 86 days. The longest consecutive day streak was 146 days in 2000-2001.

Huge Snowpack Again Means Flooding This Month And Next

The deep snow cover throughout the area with more than 20 inches of snow across much of western and southwestern Minnesota and the eastern Dakotas poses a large threat for spring snowmelt flooding. Some kind of flooding is expected along nearly all of the Red and Minnesota Rivers, the lower St. Croix, and the Mississippi River from the Twin Cities Metro downstream to Illinois and Missouri. The James River in North Dakota is likely to flood and there may be enough flooding along Devils Lake in North Dakota to disrupt the main east-west railline along the lake as well as flood many residences. Major flooding is likely along the Mississippi from its junction with the Minnesota River and along the Red and Red Lake Rivers. In the immediate St. Cloud area, the Sauk River is likely to produce at least minor flooding in Waite Park and north St. Cloud and the Mississippi could crawl out of its banks along the low areas in Sauk Rapids and along the river north of Cathedral High School in St. Cloud. This doesn't count ice jams, which were a major problem last year.

Colder Than Normal, But Not As Cold As It Seemed

The long period of snow cover and colder than normal weather in long stretches has made the winter of 2010-2011 seem like it's been going on forever, but the temperatures statistics from the St. Cloud Regional Airport show that it's only been a little colder than normal. February 2011 had an average temperature of 14.1°F, 1.9°F colder than normal. That's the most below normal of any winter month. Still, all three winter months had average temperatures between one and two degrees colder than normal, so the winter season ended up with an average temperature of 11.6°F, 1.6°F colder than normal. Both 2007-2008 (10.5°F) and 2008-2009 (9.4°F) were significant colder than this winter.

The persistent cold (no high temperature above 37 degrees from November 29 through February 12) let up a bit during a mid-February thaw. Coming on the heels of a six-day cold streak with colder than zero lows (coldest: -24 on Feb. 10) and three days with highs in the single digits, St. Cloud had at or above freezing for 7 straight days from February 11 through February 17. That warm spell was broken by the cold push that preceded the February 20-21 snowstorm.

While there were 13 more days in February with a low of zero or colder, the 38 days this season is still short of the cold season average (42.7 days) and the number of zero lows in both 2007-2008 and 2008-2009. The -24 low on Feb. 10 was our third temperature of -20 or colder this season, most than last year, but still short of the average (5.4 days) or two winters ago (12 days). St. Cloud has had only two complete days when the temperature remained at zero or colder. The normal number of days is 4.3 for a cold season.

While temperatures were a bit colder than normal this winter, fall temperatures were well above normal (2.5 degrees above normal), so there have been about 250 less heating degree days than normal for the heating season.

Early March Tough to Forecast, But...

What can we look forward to this spring? We can certain appreciate the longer days and the sun being higher in the sky. That will definitely continue. Right now, we are in a wild weather pattern with low temperatures in the -20s and -30s in the northern Prairie Provinces, but highs in the 70s and high in a good chunk of the South. That will continue through early next week, making any forecasts difficult beyond 2-3 days in advance.

On the average, March only produces 3 or 4 more days with a low of zero or colder, so we are nearly done with those. The odds of a -20 low is remote; we haven't had one in March since 1962 and 1965. We've never had a high of zero or colder in March, so we are done with that. On the other hand, March usually produces our first day with a high of at least 50 degrees (median date: March 16) and, while it would be early, last March produced our first 60-degree high on March 14 and our first 70-degree high on March 30. Having no new snow fall last March and the old snow pack melt was the key to this warmth.

Snowfall from March on can be very fickle. On the average, St. Cloud still sees 7 more days with measurable snowfall, and 11.4 more inches for the season (8.5 in March). If we gets even 3 inches of snow, this snow season would have the higher seasonal snowfall since the 64 inches in 2000-2001. March and April snowfall, however, can be very fickle. We had large totals in 2008 and 2009, but none in 2010 and only 1 inch in 2005. March averages about 5 days with measurable snowfall. What March does better than any other month is produce big snowstorms. 31 Marches have had (over the past 108 winters) at least one 5-inch snowfall with 7 of those Marches having more than one day with 5 inches of snow. Still, that only means that less than one March out of three on the average has such a big snowfall.

The average date to end continuous staring at the snow pack is March 10. Such a rapid melt is unlikely. However, last March began with 10 inches of snow on the ground (12 inches this morning) and it had all melted by March 15. Note also that the last continuous day with snow cover does not mean the end of the snow season. On the average, St. Cloud's latest day with an inch of snow cover is April 4. A rapid snow melt would also make the river flooding worse.