Trapped water threatening to blow!
 

Nearly one billion (with a b) gallons of contaminated mine water is trapped in a shaft above the historic town of Leadville, CO.

Source: Colorado town fears avalanche of water - Yahoo! News

Now it's been worsening for two years, and this year we have record snowfalls in the Rockies.

There is some real concern. That much water, pressurized could cause enormous damage. And combine that with already flood stage runoffs, which we know are going to occur, bad stuff.