Record July rain falls on Moses Lake

MOSES LAKE — It’s been a wet July in the Columbia Basin, possibly the wettest July in the region’s recorded history.

According to Andy Brown, a meteorologist with the National Weather Service in Spokane, 1.55 inches of rain was recorded falling at the NWS measuring station at the Grant County Airport during the first 10 days of July, far more than the previous recorded record of 0.5 inches.

“It blew the old record out of the water,” he said.

Brown said the NWS began recording rainfall information in Moses Lake in 1947. However, the weather service failed to keep records for 16 years beginning in 1985, and so it is unclear whether rainfall for the first 10 days of July is a record or not.

“It is significant based on the data that we have,” Brown said.

According to Joey Clevenger, an NWS meteorologist in Spokane, nearly 1 inch of rain was measured in the weather service’s Moses Lake rain gauge in the 24 hours from noon Wednesday through noon Thursday, with much of that falling Thursday morning.

“That was a good rain shower overnight for Moses Lake,” Clevenger said.

The rains have kept street and stormwater crews with the city of Moses Lake busier than they would be in a normal July unclogging drains and making sure the giant puddles which formed as a result could dissipate properly, according to an email to the Columbia Basin Herald from Stormwater System Manager Brad Mitchell.

“The biggest contributor to most of today’s street flooding had to do with overgrown trees and their associated debris blocking the inlets,” Mitchell wrote Thursday.

Mitchell also blamed some of the problems on debris from 4th of July fireworks, latex gloves, gravel, and plastic cup lids clogging up stormwater grates and drains.

“The Stormwater Department spent the first half of the morning clearing debris from catch basin inlets to keep stormwater within the network. The remainder of the day was spent removing excess water and cleaning catch basins that were plugged,” Mitchell wrote.

In fact, Mitchell added the storm set city storm and street crews back nearly a week on routine summer maintenance, inspections and street cleaning.

According to Washington State University’s AgWeatherNet — a network of state and private weather monitoring stations placed largely in rural areas — the amount of rain measured around the region in the 24 hours from mid-Wednesday to mid-Thursday varied considerably, from 0.7 inches northeast of Royal City to 0.2 inches near Warden, 0.37 between Quincy and Ephrata, and none recorded in Othello.

Brown said Ephrata set a daily rainfall record on July 6, with 0.26 inches measured at the Ephrata Municipal Airport. The NWS measures Moses Lake rainfall at the Grant County International Airport.

According to the NWS, as of early morning Thursday, 4 inches of precipitation have fallen on Moses Lake since the beginning of 2022, far greater than the 1.65 inches that fell during the same period in 2021 but less than the 4.53 the region normally receives. However, according to Clevenger, that figure doesn’t include much of the precipitation that fell Thursday morning.

It’s an improvement, but not enough to end the region’s drought. According to data posted by the U.S. Drought Monitor, a joint project of the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration and the University of Nebraska, much of Eastern Washington is still listed as abnormally dry or in moderate drought.

According to Nathan Santo Domingo, a field meteorologist with AgWeatherNet, this year’s wetter and cooler weather in the Pacific Northwest is the result of a La Nina, which is upwelling of cooler water in the Pacific Ocean around the equator from South America all the way west to Papua New Guinea. Santo Domingo said La Nina changes where thunderstorms set up in the far western Pacific, and that has a cascade effect on weather patterns especially in the Pacific Northwest.

One of the biggest effects of the La Nina is the disruption of the normal summertime high pressure ridge that forms off the coast of British Columbia.

“That’s our typical summer pattern,” he said. “In La Nina, you have more low pressure in the Gulf of Alaska.”

Which means more rain and cooler temperatures, Santo Domingo added, noting that meteorologists are moderately confident the La Nina will persist into the coming winter.

“We’ve not had the strong ridges that we get in hot summers,” Clevenger said of this year’s La Nina. “So we’re getting a cooler flow pattern and more marine air.”

Clevenger said the forecast for the next week sees a ridge building up, which should bring warmer weather — more normal July heat and dryness — to the region until the end of next week. After that, he said NWS weather models suggest another patch of low pressure is expected to roll through the region beginning with more rain and cooler weather.

“It sure beats the 120-something heat we had last year,” he said.

Charles H. Featherstone can be reached at cfeatherstone@columbiabasinherald.com