February 2010 and Winter 2009-2010 St. Cloud Weather Summary

The roller-coaster winter of snowfall continued in St. Cloud during February. During the first 9 days of February, 9.1 inches of snow fell, more than the normal amount for the entire month (7.3 inches). However, a very dry weather pattern developed for most of the final three weeks of February, so the monthly snowfall totaled 9.2 inches, still nearly 2 inches above normal. There was 0.77 inch of liquid locked up in the snowfall, 0.18 inch higher than the normal February total.

February temperatures ended up being slightly colder than normal. The average Saint Cloud February temperature was 15.4°F, 0.6°F below normal. There were 9 days during February with a high of at least 30 degrees, but the dry conditions during most of the month usually produced clear, calm nights. That allowed temperatures to drop to zero or colder 11 times. These large spreads between high and low temperatures kept the average temperature just below normal without really having any arctic air outbreaks.

Even though February ended with 11 inches of snow on the ground, the total snowfall for meteorological winter (Dec 1-Feb 28) was 28.3 inches (astronomical winter ends on March 20 at 12:32 PM CDT), just 2.0 inches above normal. What is causing the potential problem is that most of it is still on the ground, as will be noted later. Total precipitation was 2.80 inches, 0.68 inch above normal. That's nearly the amount of the rain and freezing rain storm we had on January 21-25. This storm produced .72 inch of precipitation, but only 0.9 inch of snow.

The temperatures for the three-month period averaged 0.7 degrees colder than normal (21.8 degrees). This is somewhat of a surprise during an El Nino winter as temperatures in Minnesota average warmer than normal. However, a closer look shows that El Nino winters have a nearly equal chance of normal and above normal temperatures. And, we have seen the effects of the El Nino event with cool and wet conditions in the southern and southeastern US this winter.

Snow Surges and Busts in St. Cloud

Saint Cloud has had some odd snow surges and busts during the cold season so far. October ended up tying for the 10th snowiest October with 2.5 inches, then November was one of only 13 Novembers with no measurable snowfall in St. Cloud. December produced 18.2 inches, the 7th snowiest December on record, followed immediately by 5th least snowy January with only 0.9 inches.

In more detail, St. Cloud had 18.2 inches of snow during December (normal: 9.0 inches), 12.7 of which fell during the Christmas week storm, only the 16th storm in St. Cloud records that produced at least a foot of snow. Then, between December 27 and the end of January, only 0.9 inch fell (normal 12.2 inches), although there was still around half an inch of rain during a freezing rain and rain storm late in January. During the first 9 days of February, St. Cloud picked up 9.1 inches (normal: 2.3 inches), but only got 0.1 inch from February 10 on (normal: 5.0 inches). It all leads to a cold season total snowfall of 30.8 inches, still 5.2 inches short of normal.

More Snow to Our West Leads to Flooding Threat

In the region, St. Cloud had a relatively low seasonal snowfall total. There has been much more snowfall to our west (Fargo: 46.6 inches and Sioux Falls: 56.6 inches). That still leaves more than 20 inches of snow from the eastern Dakotas into southwest Minnesota, as you can see on the NWS NOHRSC Upper Midwest snow depth chart. This week's Minnesota State Climatology snow depth map shows the snowpack down below a foot in a large swath from Lake Winnibigoshish through St. Cloud and into the Twin Cities. However, there are still more than a foot and a half on the ground along the Buffalo Ridge and in southwestern Minnesota, most of the North Shore, and parts of the Red River Valley. This heavy snow pack, which contains 4-8 inches of water, is what is causing the potential flooding threat in the Red River, Upper Minnesota River, and Mississippi River in St. Paul and Hastings. That threat of at least minor flooding includes the Long Prairie River in Long Prairie and the South Fork of the Crow River in Delano. There is also a very good chance of flooding in parts of the Missouri River Basin. including places like Bismarck, Mitchell, Pierre, Yankton, and Sioux Falls. For areas of central and southern Minnesota, the risk of at least some flooding is 60-80%

Record-Breaking Mid-Atlantic Snow Higher than Central US

However, the mid-Atlantic and southern US have been absolutely clobbered with snow. Places like Philadelphia, Baltimore, Washington, and Atlantic City have picked up more snow than anywhere in Minnesota or the Dakota, even though the annual average of snow is less than 20 inches. The snowfall in Baltimore has broken 80 inches, more than double St. Cloud's total. In fact, there have only been three winters in St. Cloud history with as much snow as this year in Baltimore or Philadelphia. St. Cloud's snowiest year dumped 87.9 inches during the 1964-1965 season. You can see the comparisons in the NWS Twin Cities report on regional and national snowfall.

On the other hand, St. Cloud has been staring at its snowpack far longer than the eastern cities. We've had at least an inch of snow on the ground since December 9, marking 82 straight days with a snow cover. However, we had 102 straight days with a snowpack last winter and 117 straight days with a snowpack in the 2007-2008 winter.

We also need to be a bit cautious to write off the snow season, despite the streak of mild weather. During an average year, St. Cloud gets 11 inches of snow in March and April (and rarely in May). Only 4 Marches since 1995 have had less than the normal 8 inches of March snow. There have only been two Marches in the past 30 years with no measurable snowfall: 1980 and 2000. During the past two winters as well as the winter of 2006-2007, we had a large chunk of our seasonal snowfall from late February through April (27.1 inches out of 31.8 total inches in 2006-2007; 36.0 inches out of the 52.2 inches total in 2007-2008; 22.8 inches out of 53.9 total inches in 2008-2009). However, as long as the steering wind pattern continues to set up with a strong southern US storm track and another track across central Canada, storms will continue to dodge us.

A continuation of our weather from the past two weeks would also mitigate the flooding threat by having as slow a melt as possible. It looks like that will continue through the first week of March.

However, the split flow around Minnesota has led to several days with air pollution problems due to the build-up of small particles trapped near the ground. The Twin Cities have had 8 days of the past 30 during which the Air Quality Index has worsened into the unheathful for sensitive groups (over 100), according to the Minnesota Pollution Control Agency. St. Cloud has had 5 days in which the AQI has climbed to at least the upper half of the moderate category since the start of February, including one day of unhealthful for sensitive groups on Feb. 5. In the upper end of the moderate category, people with a history of asthma or sinus problems end up struggling with sinus headaches.

As long as the split flow pattern continues, the St. Cloud area will have periods of poor air quality since there won't be a good continuous push of cleaner Canadian air masses.