Rocky Low
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You may of heard of a "Rocky Mountain High," but it's actually those Rocky Mountain lows that meteorologically anyway plague the U.S. in the winter. Hi, I'm Dave Thurlow from the Mount Washington Observatory and this is The Weather Notebook.

Rocky Mountain Lows are snowstorms that often develop in or near Colorado and then move on to cause trouble on the plains and points east. You can pin part of the blame on the mountains of the Mountain State.

When the jet stream cuts from west to east across these mountains, the terrain helps to generate low pressure on the lee side--the flatlands of eastern Colorado. This is one of the most fertile grounds in the country for breeding low-pressure areas. Before long, a Colorado low may be sucking in moisture from the Texas Gulf Coast and mixing it with moisture that's made the long trek from the Pacific. In a day's time, this storm could be causing blizzard conditions across Kansas, Nebraska, or Iowa.

At other times the jet stream makes a twist and cuts off into a swirl that parks over the Four Corners region. This pulls moisture upslope, right against the front range of the Rockies. This scenario gives Colorado some of its most phenomenal snow totals--like the 75.8 inches that fell on Silver Lake on April 14, 1921. A six-foot-three inch tall person would stand just below a snowfall this deep. That's truly a Rocky Mountain high.

Thanks all this week go to writer Bob Henson for putting together our field guide to snowstorms so to speak. You can check it all out at mountwashington.org. The Weather Notebook is underwritten by Subaru, the beauty of all wheel drive.