Somewhere in Washington today, drops of melting snow join into a rivulet that grows fatter as it heads toward a stream. If the snow melts too quickly, those streams can turn into floods, and the lack of snow into drought.

Spring in the Northwest, once a time of joy and relief, is now also tinged with anxiety. As shrinking glaciers and flooding rivers warn of global warming's impact on the region, bankers, insurers, investors and lawyers are thinking more darkly about spring and those drops of water. Increasingly, they are using climate science to assess the potential economic consequences to our state.

Those consequences are almost too vast to quantify: more frequent forest fires, extra hatches of bugs, more asthma, droughts in some places and flooding in others. Changes in sea level could cover tens of thousands of acres of low-lying land with water, including much of the Port of Olympia. If weather events combine sea-level rise with flooding or erosion on those same coastlines, thousands of people could lose their homes. If heavy rains fall on a steep hillside where forest fires burned recently, a devastating mudslide results.

With drought more common than ever before, bankers are limiting loans to farmers whose land faces too much drought risk. Insurers are helping to educate consumers about building near wilderness prone to forest fires. Several Seattle law firms have already created "climate impact" groups to help corporate clients define the slippery new risks that could come from climate change; for example, the possibility that government could force companies to restrict carbon emissions.

"This has gone from a sleeper to a hair-on-fire issue in the past 90 days," said attorney Craig Gannett, of Davis Wright Tremaine in Seattle.

In December, the Washington Department of Ecology published "Impacts of Climate Change on Washington's Economy," a 119-page report that is one of the first efforts to quantify the impact of this global phenomenon on a single state.

"Human society has shoved the climate system into a new territory, in which there will be changes that are hard to predict," says Bob Doppelt, who led the report team. He believes that extremes of weather could very well be more common. Doppelt is affiliated with the University of Oregon.

Such extremes can exact a huge cost. Consider this past winter. Heavy snow, ice and wind toppled trees and destroyed transmission lines that resulted in an estimated $100 million in restoration costs to Puget Sound Energy. Early estimates put the cost of flood and wind damage to King County parks and levees at about $30 million, the cost for roads at about $12 million. And that did not include the untold millions from lost productivity when an estimated 2 million people went without electricity in December, some for 10 days. Across the region, factories, stores and hotels had to shut down.

"The power of nature and human vulnerability was vividly illustrated with this storm," said Carolyn Duncan, communications manager for King County. "It tested our systems in a way we haven't seen in years."

Although you can't blame any one storm on climate change, Doppelt says business and government need to adopt a new way of thinking, a new way of anticipating and preparing for what were once rare crises.

The hope is that adjusting and adapting can help farmers, resort owners, shellfish growers, insurers and others reduce the potential for economic disaster and perhaps find ways to prosper from new opportunities.

Philip Mote, the state's climatologist, operates from a small cubicle, in a warren of other cubicles, in a gray building behind a bank on a commercial strip in the University District in Seattle. He is a member of the Climate Impacts Group, which contributed to Doppelt's report. After 10 years of talking about climate change, Mote says people are finally listening. As well they should. Consider the following: