Heavy rain in Anchorage triggers road closures and floods basements

Heavy rain deluged Anchorage Wednesday and much of Thursday, swelling creeks, triggering road closures and overwhelming storm drains in some parts of the city.

The burst of precipitation came courtesy of an atmospheric river of precipitation bearing down on Southcentral that also triggered flooding in Seward on Wednesday. Waterways around Anchorage overtopped their banks, flooding sections of trails and roads, as high groundwater seeped into basements.

The storm total from when the rain started falling Tuesday evening until Thursday afternoon was just over 3 inches, according to a National Weather Service gauge in Sand Lake. A flood advisory expired at 4 p.m., the weather service said: “Flood waters are receding and the heavy rain has ended. Flooding is no longer expected to pose a threat. Please continue to heed remaining road closures.”

Chester Creek at Arctic Boulevard crested Thursday afternoon at about 5.5 feet, just over moderate flood stage of 5 feet, and appeared to be dropping, according to river gauge data. Campbell Creek at Dimond Boulevard had crested just over minor flood stage of 20.5 feet, according to the data.

Several other areas saw flooding, including one neighborhood in South Anchorage at East 74th Avenue and Nathan Drive near Little Campbell Creek, city officials said. Municipal crews set up pumps to clear storm drains overwhelmed by water or flooded by nearby creeks, according to municipal street maintenance manager Paul Van Landingham.

Van Landingham said officials expected high water in the usual places as creeks started rising Wednesday but realized overnight that conditions were more widespread.

“We were prepared for some localized flooding. But we’re responding to some that we typically do not have to worry about. It’s been a long time since I’ve seen the creeks at this level,” he said, adding he’s worked for the municipality for 28 years.

Municipal crews worked through the night into Thursday and were expecting to do the same into Friday, Van Landingham said. A brief break in the rain might give them a chance to pump out high water before more heavy rain is forecast to return Saturday and Sunday.

Once the water recedes, he said, crews will be on to the next job: patching potholes.

Sections of the municipal trail system experienced significant flooding, according to an update Thursday from the Anchorage Parks and Recreation Department that accompanied a photo of the Chester Creek Trail at C Street totally under water.

City trails had sections still submerged by Thursday afternoon, officials said. Six inches to a foot of water covered some low-lying areas and water pooled in numerous underpass tunnels, according to Mike Braniff, municipal parks and recreation department director.

Braniff asked trail users to use caution, especially in places with deep water like Chester Creek at C Street, where several feet remained pooled over the trail.

“We’re asking the public to be patient with us,” he said.

Rising water on Thursday morning closed northbound traffic on Spenard Road at 19th Avenue and Hillcrest Drive, according to an Anchorage Police Department alert. There were also flood-related lane closures at 36th Avenue and MacInnes Street.

The phones at Dry Out Systems in Anchorage rang steadily Wednesday, one employee there said between calls. While many reported flooded basements, he said, it was also important to check crawlspaces for water.

This latest concentrated burst of rain comes after an already wet summer.

Since July 12, the Weather Service had measured more than 5.6 inches of rain at the agency’s Sand Lake offices as of Wednesday, according to meteorologist Michael Kutz. That’s more than half of the 10.74 inches that’s fallen since the start of the year.

Thursday’s total as of about 4 p.m. was 1.12 inches, for a storm total of 3.08 inches, according to meteorologist Chris Quesada.

The year-to-date normal average is 6.8 inches, Kutz said.

This storm is expected to diminish into a “break” of scattered showers by Friday — before a fresh storm moves in this weekend and brings more rain through Sunday, he said. “We’re kind of stuck midflow on an atmospheric river.”

Anchorage hit a daily record for rain on Wednesday, with 1.33 inches measured at the National Weather Service station in Sand Lake, the agency said. The prior record, .7 inches, was set in 1980.

A flood advisory in place for Anchorage most of Thursday warned of minor flooding in low-lying and poor drainage areas and elevated flows along area creeks and streams, ponding on pavement and debris clogging storm drained and ditches.

A flood warning was also in effect until Saturday afternoon for the Susitna Valley, where 2 to 4 inches of rain fell over some areas of the Lake Creek, Skwentna, and Yentna river basins over the past 48 hours. Rivers were expected to rise into Friday before cresting, with an additional rise of 1 to 2 feet possible.

A satellite chart shows a long stretch of moisure settling down over the North Pacific “basically pumping moisture over the top of us” and slowly moving to the east, Kutz said.

Correction: An earlier version of this story misspelled National Weather Service meteorologist Michael Kutz’s name.