Three out of four Mossyrock Dam spillways open as Riffe Lake remains swollen from continued rainfall

As rain continues to fall daily in East Lewis County, three out of the four spillways on the Mossyrock Dam remain open as Riffe Lake remains swollen with a water level nearly 40 feet higher than it was on Dec. 7.

From Dec. 7 through Dec. 14 during the atmospheric river storms, the level rose from around 720 feet up to almost 760 feet, according to National Oceanic and Atmospheric Administration (NOAA) gauges.

As of 1 p.m. on Thursday, Dec. 18, Riffe Lake’s water level was at 756.13 feet.

Downriver, the Mayfield Dam has also been releasing elevated flows, leading to a flood warning in Toledo and surrounding areas.

“Dam operations to maintain a safe flood pool for area dams could maintain elevated flow levels or they could raise or lower levels downstream of the dams. Dam regulation can change rapidly,” the NOAA stated, adding, “At 25,000.0 cfs, the Cowlitz River will flood the reach from Mayfield Dam downstream through Toledo … At 4 p.m. Thursday the flow was 28,500.0 cfs …  Flood waters will inundate some farmlands and several roads, mainly near Toledo … The maximum river flow in the 24 hours ending at 11 p.m. Tuesday was 28,700 cfs. The river is expected to remain near 28,800 cfs through the weekend.”

While precipitation is still forecast with both rain and snow predicted, flood warnings for East Lewis County appear to have been rescinded.

However, Randle residents were expected to see some minor flooding Friday, as NOAA’s Cowlitz River gauge is predicting a rise in the river’s level from Thursday afternoon, with waters expected to crest at around 10 a.m. on Friday, Dec. 19, at 19.68 feet.

Gauges monitoring lake level, river inflow and dam outflow rates at Riffe Lake can be found on NOAA's website at https://tinyurl.com/mprsud9h. 

Data from NOAA’s gauges on the Cowlitz River in Randle can be found at https://water.noaa.gov/gauges/RAWW1.