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Snowpack — Shrinking Or Growing?

by Marlo Lewis on May 24, 2011

in Blog, Features

A staple of climate alarmism is the claim that snow pack in the arid West is shrinking and melting earlier in the spring season, diminishing supplies of water needed for irrigated agriculture in the hot summer months. But this year, snow pack is at record highs. Indeed, snow is piled so high that the big worry is not about summer drought but flash floods.

Declining snow pack figured prominently in both EPA’s and the California Air Resource Board’s (CARB’s) climate change regulations.

EPA’s Endangerment Rule [p. 66532], which obligated the agency to establish greenhouse gas (GHG) emission standards for new motor vehicles, states:

Climate change is causing and will increasingly cause shrinking snowpack induced by increasing temperature. In the western United States, there is already well-documented evidence of shrinking snowpack due to warming. Earlier meltings, with increased runoff in the winter and early spring, increase flood concerns and also result in substantially decreased summer flows. This pattern of reduced snowpack and changes to the flow regime pose very serious risks to major population regions, such as California, that rely on snowmelt-dominated watersheds for their water supply.

Similarly, CARB’s Initial Statement of Reasons [pp. 12, 17] for regulating GHG motor vehicle emissions declares:

In California, large accumulations of snow occur in the Sierra Nevada and southern Cascade Mountains from October to March. Each winter, at the high elevations, snow accumulates into a deep pack, preserving much of California’s water supply in cold storage. If the winter temperatures are warm, more of the precipitation falls as rain instead of snow, and water directly flows from watersheds before the spring snowmelt. Thus, there is less buildup of snow pack; as a result, the volume of water from the spring runoff is diminished. . . .If the climate shifts toward a severe drought, not only will more irrigation be needed, but also the snow pack at higher elevations will be lacking. This can be disastrous for producers that grow fruit trees and vines that will require years to reestablish production.

Of course, one or even several years of heavy snowfall do not a climate trend make, and the climate crusaders at EPA and CARB do not deny that natural variability can dominate weather patterns from year to year. Nonetheless, it’s safe to say that neither agency anticipated anything like the snow pack that’s been piling up this year.

“Thanks to a blizzard-filled winter and an unually cold and wet spring,” reports the New York Times, “90 measuring sites from Montana to New Mexico and California to Colorado have record snowpack totals on the ground for late May, according to a federal report released last week.” Come June, the giant snow packs could melt “mildly if weather conditions are just right, or wildly and catastrophically if they are not,” says the Times. But, “No matter what happens, the snows of 2011, especially their persistence into late spring, have already made the record books.”

Although the Times article focuses on flood risk and the preparations disaster officials are making, it also notes an important upside:  

Hydrologists, meanwhile, are cheering what they say will be a huge increase in water reservoir storage for tens of millions of people across the West. Lake Mead and Lake Powell, two huge dammed reservoirs on the Colorado River battered in recent years by drought, are projected to get 1.5 trillion gallons of new water between them from the mammoth melt. 

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