National Weather Service United States Department of Commerce

Atmospheric River in the Pacific Northwest and Northern Rockies this Weekend

A Pacific storm and atmospheric river will impact the Pacific Northwest states and northern Rockies this weekend, bringing locally heavy low elevations rain and heavy high elevation snow in the mountains. By Sunday over the Interior Northwest, rain combined with snowmelt will increase the risk of flood hazards. Flood Watches are in effect. Read More >

On the evening of March 31st, 2009, Tim Tevebaugh was driving home from work east of Craigmont in the southern Idaho Panhandle (see map below). Across the rolling hay fields, Tim saw a very unusual phenomenon. The snow rollers that he took pictures of are extremely rare because of the unique combination of snow, wind, temperature and moisture needed to create them. They form with light but sticky snow and strong (but not too strong) winds. Some snow rollers are formed by gravity (i.e. rolling down a hill), but in this case, the snow rollers were generated by the wind. These snow rollers formed during the day as they weren't present in the morning on Tim's drive to work.

Based on estimations from Tim as well as the blades of grass in the picture, most of the snow rollers were about 18" in height, while the largest rollers were about 2 feet tall.

Click on the thumbnails below for a full-size image.

 

Snow Rollers - Click for larger image  Snow Rollers - Click for larger image  Snow Rollers - Click for larger image

Snow Rollers - Click for larger image  Snow Rollers - Click for larger image  Location of Snow Rollers - click for larger view