Alaska's heavy snow pack, coupled with cooler-than-average temperatures, is a recipe for flooding this year. Hydrologists with the National Weather Service delivered the news during a roundtable discussion on the issue Thursday morning in Anchorage with U.S. Sen. Lisa Murkowski, R-Alaska.
Alaskans are already feeling the effects of break up, a phenomenon that for urban Alaskans can be measured by gallons of windshield washer fluid used, Murkowski pointed out. The more you need, the longer you're in the grips of the freeze-thaw cycle that doesn't end until summer arrives.
"This winter has been very much a see-saw. November was cold, December was warm. January was cold, February was warm. March was cold, and now the question is: 'What's April going to be?'," said Scott Lindsey, a hydrologist with the weather service's river watch program in Anchorage.
Because March was cooler than normal and April also looks chilly, forecasters are calling for "above-average" flooding. A cold spell leading into break up increases the likelihood of what Lindsey calls the "prime trigger" for break-up floods: rapid warming in late April and early May.
If villages always experience some flooding in the spring, they should prepare for moderate flooding. Communities that seldom flood should expect to get wet.
Villages along Alaska's Yukon and Kuskokwim rivers have front-row views of the dynamic power of nature at work when ice and snow suddenly turn to water. Ice jams have the potential to flood communities upriver -- or send a tidal wave of water and ice to villages downriver when the jams finally give way.
An extreme example came in 2009 when the small Interior community of Eagle near the Yukon border suffered $13 million in damages when a severe ice jam and subsequent flood wiped out the entire old village site, including much of the town's waterfront homes and businesses. Huge ice chunks snapped trees like toothpicks and ripped homes off their foundations.
The National Weather Service's River Watch program has started monitoring conditions, and will increase its vigilance in the coming weeks. Observers in planes fly the rivers, taking pictures and reporting what they see while also publishing field reports from locals.
Villages along the state's river systems are encouraged to make sure they have evacuation and shelter plans in place, so they're prepared to manage the situation and keep people safe if the call of an approaching flood comes.
Contact Jill Burke at jill(at)alaskadispatch.com