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Flood Threat in West Grows

May 30, 2011; 12:20 PM ET

The mighty Mississippi lived up to its name this spring, inundating many places from north to south with record flooding levels in some areas. I have had several posts in the past month about the risk of flooding, potentially severe flooding, in the West from the Salt Lake Basin on north to Montana and west throughout the Northwest and south into California. Some flooding has been occurring in Montana in recent days from the result of snowmelt and locally heavy rain. This has received some national media attention. But the potential for flooding in the rest of the West has gone pretty much unheard of except in some local media outlets, and of course here on AccuWeather.com.

The fact is record snowpack from the winter is still waiting to melt after a very cool May. The melting is well behind schedule. There is a lot more snow in the high country than there should be waiting for the warm weather to come. As I have said before, flooding is going to occur on a lot of rivers leading out of the mountains. The only question is how bad it will become.

Here is a picture of the snow water equivalent that was still locked up in the extensive snow cover as of May 29.

There are large areas where the existing snowpack continues to have 20 to 40+ inches of water locked in it. That would be incredible even if it were early April. That is a lot of water still wrapped up in the snow, and water that still has to find its way down the watershed. It's a time bomb with a fuse of unknown length. If it were to warm up quickly as stay warm for an extended period of time, rapid melt would occur and quickly overcome the river systems in many areas. The only good news is that it looks like it will stay cooler than normal through the end of the week and weekend. The bad news is that some rain and high-elevation snow will fall from northern California to the northern Wasatch and across the Northwest into the northern Rockies. At least two more storms move in off the Pacific, one Wednesday and Thursday, and another late in the weekend and early next week.

I will have some more interesting water information tomorrow.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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About This Blog

Ken Clark
Ken Clark's Western U.S. weather blog tackles daily weather events with commentary from one of the most experienced and trusted Western U.S. weather experts.

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