Snowfall in Washington state fluctuates greatly. Some years an El Nino delivers less, some years an El Nina dumps. The 2014-2015 winter was the worst in decades, but not the worst in history. Why then are the glaciers at their smallest in 4,000 years?

The biggest problem, says glaciologist Mauri Pelto, is the snow blanket that insulated glaciers is gone. That means the bare ice is exposed and melting all over the Cascades.

This summer saw the biggest loss of volume in 50 years.

Sure, it's just one bad year... and if there are bad years every 50 years that's nothing in the life span of a glacier. Yet the scientists say Washington's glaciers have been slowly retreating since the 1980s.

Whether or not global warming had a role, smaller glaciers will provide less melt water to Washington's streams and rivers. This will impact farming, salmon and drinking water supply.