Flood danger passes, ice dam still unbroken

Posted: Sunday, September 02, 2001

Last week's rainfall and subsequent flood warnings in the Kenai River basin drew nervous eyes to the high waters but passed without setting off any major alarms. However, hydrologists say there may still be cause for concern.

So far, only minor flooding has occurred, the worst being at the Primrose campground at the southern end of Kenai Lake. According to a National Weather Service/Alaska River Forecast Center report issued Friday, water up to 17 inches in depth was expected to remain over the Primrose access into Saturday morning. But officials say this type of flooding is not out of the ordinary for Primrose, and the flood warning for the area expired Saturday at 4 p.m.

"There hasn't been much going on at all," said NWS/ARFC Hydrologist Dev Gangadean. "The access road to the Primrose campground has some flooding on it, but that's almost routine. The road hasn't even been closed."

Heavy rainfall earlier this week over the upper portion of the Kenai basin swelled water levels in the Kenai River and its tributaries, the NWA/ARFC report said. That extra water drew some watchful eyes to the river, but the rain let up and allowed the waterways to crest without any major flooding.

"We've been getting a lot of calls the last few days about what's going on in the Kenai," Gangadean said. "We were kind of worried a few days ago, but once we saw the rain was going to let up before the river really piled up, it wasn't that big of a deal."

The Snow River rose 4 feet from the rainfall but crested Tuesday and began to recede. Smaller streams crested Friday and started draining as well. The upper Kenai crested Friday evening at around 13.4 feet.

The NWS/ARFC expected the lower Kenai to crest Saturday night or Sunday morning south of the Kenai Keys residential area at a height of 12 feet at the Keys and 13 feet at the USGS gage. The NWS update warned flooding was a possibility in the Keys area, but Gangadean predicted at noon Saturday that it wouldn't be a problem unless there was more rainfall.

While the flood scare has passed, hydrologists are still monitoring weather forecasts and the Snow River Glacier Dammed Lake that is due to drain anytime now.

The lake, formed behind the Snow Glacier north of Seward, typically drains into the Snow River every two to three years. The last time it drained was from September to October in 1998. According to Gangadean, the lake has gone for four years without draining before, but that is not its normal behavior.

"We haven't seen any sign of anything yet," said Gangadean. " But it's probably going to happen within the next month. One of our more experienced hydrologists says it typically waits for the first high frost up there."

By itself, the lake draining would not necessarily be cause for concern. But if the draining coincides with rainfall, it could lead to more severe flooding.

"If the lake drained with what was going on last week, it would have been a true mess," said Gangadean. "It just depends on what is going on beforehand. Like in 1998, the lake drained when nothing else was happening, so it wasn't a problem."

More rain is not expected in the Kenai area until Tuesday or Wednesday. Gangadean estimated it would take about half the amount of precipitation that fell during last week's storm to cause more flooding problems.

"The probability of the glacier running out at the same time as a major storm is maybe about one in 20," Gangadean said. "So it's definitely worth watching. And that's why we're here."

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