Winter Storms Improve Calif. Drought Conditions

(Feb. 16) -- The damaging and extreme side of the wild weather this winter has dominated the headlines, but there's been at least one benefit of this weather pattern: A three-year drought in California has improved dramatically in recent weeks, and with additional storms on the horizon, the drought might be completely eliminated before spring arrives.

The water problems began when the 2007 rain year (Oct. 1, 2006, through Sept. 30, 2007) was below normal, and below-average rain years in 2008 and 2009 resulted in widespread drought conditions. Gov. Arnold Schwarzenegger declared a drought emergency in February 2009, and the drought continued for the rest of the year. By late December, nearly the entire state was in a moderate drought (indicated by the beige areas on the map below) or a severe one (indicated by orange areas).

In addition to fueling concerns about immediate and long-term water supplies, due to reservoir levels being dangerously low, the drought has caused billions of dollars in agricultural losses and a high unemployment rate among agricultural workers over the past couple of years. If the drought situation wasn't improving, each year would seriously compound the problems, resulting in hundreds of thousands of acres of empty fields, additional restrictions on water usage and a greater number of unemployed.

In other words, a very bad situation could have become disastrous if the rain hadn't arrived.

The significant improvement began in the second half of January when a series of moisture-laden Pacific storms brought enormous amounts of rain and mountain snow to California. As much as 20 inches of rain and 10 feet of mountain snow fell in parts of the state in one week. To put those numbers in perspective, New York City averages 43 inches of rain per year, and Buffalo, N.Y., averages about eight feet of snow per year. Additional storms in February have brought more moderate amounts of rain and mountain snow.

After the recent storms, the drought situation in California has greatly improved. While a fairly large portion of the state is still categorized as abnormally dry (indicated by yellow on the map below), with a moderate or severe drought limited to the north, much of the state (indicated by the white areas) is no longer in a drought at all.

It's a remarkable change of fortune during a short period of time, and not surprisingly, it's come at a cost of its own. The deluge of rain has caused flooding and mudslide problems, especially in areas where wildfires in recent years have stripped the ground of vegetation.

Drama and imbalance -- unfortunately, that's the nature of California weather. Unlike many areas of the country, the state has a well-defined "rainy" season, which is generally from late fall through early spring, but even that's a misnomer. It's not so much a rainy season as it is a period during which rain is possible. Significant rain simply does not occur during most of the year, which means the state depends on only a few months for storms to replenish its water supply. That's why droughts can span years -- and even the better part of a decade.

When the storms come, though, they often come with a vengeance. Pacific storms, which are frequent in the winter, are not always directed toward California, but when they are, there's often too much rain in a short period. This is what happened in January, and it appears as if another such period of stormy weather might occur from the latter part of February into March.

If this new round of Pacific storms does materialize, look for another round of flooding and mudslides -- and the possibility that the three-year drought will become a distant memory.