Saturday, January 05, 2013

What a difference a year makes...

Top image shows satellite image of snow cover
Bottom image shows webcam image from Emerson
The  images above show the stark contrast in snowcover over the southern Prairies and northern plains this year compared to last year.  Last year saw very mild conditions through December and early January, along with well below normal snowfall. In fact, up to Jan 1st, Winnipeg had received only 27 cm of total snowfall for the season, with only 5 cm all of December.  The lack of snow was quite evident from satellite images which showed a notable lack of snowcover into early January over much of southern SK, southern MB, and the northern plain states. The lack of snowcover allowed temperatures to soar to record high values in early January, including +6.7C in Winnipeg on the 5th, 11.5C in Gretna, and an all time January high of 13C in Fargo ND.

This year it's been a lot different, but certainly more typical for winter in this part of the world. Winnipeg has seen 75 cm of snow through Jan 1st, about 3 times the amount from last year, and almost twice the normal up to this point.  Snowcover is much more widespread across the Prairies, with much of the area covered in a blanket of white (see satellite image above)  Snowcover has been greater throughout much of the US as well, with about 65% of the country snowcovered compared to only 23% at the same point last winter. Snowcover is a very efficient heat deflector, as incoming solar radiation reflects off the bright snow surface back into space, making it more difficult for the earth's surface to warm up. The result is colder temperatures, which we've been seeing this winter compared to last winter.

No comments:

Post a Comment