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Strongly Terrain Enhanced Snowstorm

Duluth, MN

Dec 14 to 15, 2005

Storm overview

Orographic lift lift due to a deep layer of south-southeast winds from the surface to 500 mb, which is nearly perpendicular to the hill in Duluth, caused greatly enhanced snowfall in the higher elevations. At the same time, warmer temperatures at the bottom of the hill retarded accumulation. Snow on top of the hill was clinging to trees and other objects. Snow toward the bottom of the hill was just laying on top of the grass. A few bands of snow off Lake Superior affected the city when winds shifted to a more easterly direction. The snow bands primarily affected the central part of Duluth. These three influences on snowfall contributed to highly variable snow totals.

Event timeline

Snow started shortly after 12:30 AM on Wednesday the 14th. Snow continued through the day and the following night then ended around 9:30 AM on Thursday the 15th. As the initial surge of snow approached Duluth from the south, radar showed another area of snow blowing up along the higher terrain near Lake Superior, especially northeast of Duluth. Snow, heavy at times, fell through the overnight morning and the early daylight hours of the 14th. Another period of heavier snow, enhanced by a few bands of snow off Lake Superior, fell from 1 AM to 5 AM on the 15th. The second period of heavier snow produced accumulation rates of 1 inch per hour.

Snow totals

Snow totals ranged from 8 inches or less in the lower elevations to 12 inches along the ridge crest then to between 15 inches or more farther inland. The National Weather Service Forecast Office near the Duluth International Airport reported 15.8 inches. Personal measurement near the ridge crest of the central part of Duluth was 12.3 inches.

Storm evolution on radar

Radar mosaic images from the National Centers for Environmental Information

4 AM CST December 14, 2005

9 AM CST December 14, 2005

7 PM CST December 14, 2005

2 AM CST December 15, 2005

Surface and upper air maps showing storm structure at 6 AM December 14, 2005

Surface map from the NOAA NWS HPC

6 AM CST (12 UTC) December 14, 2005

Upper air maps from the Storm Prediction Center's upper air map archive

The wind at 700 mb from the International Falls observation site in northern Minnesota appears to be erroneous.

925 mb - (12 UTC) 6 AM CST December 14, 2005

850 mb - (12 UTC) 6 AM CST December 14, 2005

700 mb - (12 UTC) 6 AM CST December 14, 2005

500 mb - (12 UTC) 6 AM CST December 14, 2005