Winter Storm in Lower Clark Fork Region, Montana

There were two periods of impact for this storm system. During the morning and early afternoon, 06:00 MDT-15:00 MDT, snowfall rates were between 0.25 per hour and 0.50 per hour. Chains were required at Lookout Pass around 08:00 MDT. Another round of snow occurred between 16:30 MDT-18:30 MDT. Snow rates climbed to near 1 inch per hour during the evening hours. The evening snow led to chains being required at Lookout Pass around 17:45 MDT. There were also two separate vehicle accidents that led to lanes of west-bound Interstate 90 being blocked.

A low pressure system moving across the region helped develop snowfall at high elevations, including at pass level. Gusty winds also impacted the higher terrain locations. The late-season nature of the event led to additional messaging considerations.