Spring breakup flood potential

Much of the state at an above normal risk
Published: Mar. 21, 2022 at 6:56 PM AKDT
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ANCHORAGE, Alaska (KTUU) - As we enjoy longer and gradually warmer days, all the white snow still on the ground may be a cause for concern regarding breakup, which is still several weeks from now. Like any other weather-related outlook, however, there are several factors in play.

“The big thing driving our outlook this year is snowpack. We definitely have an above to well above average snowpack throughout the state so it’s available there to melt during breakup and it’s just going to be just how quickly it melts that drives the flood threat” Hydrologist at the Alaska-Pacific River Forecast Center Crane Johnson said.

That’s because if melted all at once, the Yukon, the Koyukuk, the Kuskokwim, the Susitna and the Tanana Rivers would be overwhelmed. So, it comes as no surprise that these rivers are projected to have an above normal chance of experiencing flooding as break up occurs this spring. There is good news though when looking at the actual ice thickness on the rivers.

“The few measurements we do have for ice thickness show that ice thickness is normal along the Kuskokwim to maybe slightly below normal at the the few sites we have on the Yukon and the Tanana River,” Johnson said.

Of course, temperatures will be critical to watch over the next 4-6 weeks. As in most cases, slow and steady is best, and Alaska climate specialist Rick Thoman agrees.

“So, it’s a much slower, gradual melt, that will be a very different situation than if it stays cold through the first week in April and then bang, it’s 60 degrees,” Thoman said.

Finally, no projection would be complete without factoring in a wildcard of some kind.

“While it’s unusual, it’s not guaranteed that all the snow that is going to melt has yet fallen,” Thoman said.

Thoman cautiously reminded that snowstorms may continue to occur before summer arrives.

Regardless, all indications are that’s there’s a lot of water yet to move into the state’s main bodies of water. That said, both Johnson and Thoman agree that it’s a wise course of action to take some of those initial spring flood preparedness steps right now. This way, you aren’t completely caught off guard should flooding happen quickly later on down the road.

Be sure to stay with your Alaska Weather Source team this spring as breakup occurs. You’ll be able to find the latest forecasts to keep you and your family prepared and safe on our website: alaskasnewssource.com

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