January 2005 Banded Snow Event Using the Weather Event Simulator

摘要

A banded-snow event occurred on the 12th and 13th of January 2005 over portions of Western Montana and North Central Idaho. In addition, during this same period, an arctic front pushed west of the continental divide through the Glacier Park region and eventually moved into the Flathead valley and south of Kalispell. This complex weather system produced localized snow amounts up to 21 inches over a three day period and ended up as one of the most significant snow events of the year. While the arctic boundary did produce heavy snow and near blizzard conditions close to the continental divide, most of the snowfall and public impact from this event was produced by banded snow structures which occurred west and south of the arctic boundary. It can be argued that episodes of banded snow have one of the largest winter impacts to the public in the Missoula forecast area. These events can lead to significant valley snowfall over populated areas. In this case, which was typical to similar banded events, many areas received almost no snowfall, whereas others had significant impacts due to persistent moderate to heavy snow. In particular, one of the snow bands became aligned parallel to the west-to-east oriented and heavily traveled I-90 corridor. This stationary band produced localized hourly snowfall rates in excess of 3 inches per hour and led to road closures from Bonner to 15 miles west of Drummond (areas east of Missoula).