NICK WILSON WRITES:
The NWS Navarro River gauge forecast chart now shows the river starting to rise quickly after noon today, and I expect Hwy 128 will be closed by 1 to 2 PM due to shallow flooding at the west end.
https://water.weather.gov/ahps2/hydrograph.php?wfo=eka&gage=nvrc1
A major crest peaking at 15.3 ft. is predicted about midnight tonight. That major flow will go up against a massive seasonal sandbar blocking the river mouth since last spring. There's no doubt that the river will break through the sandbar by the time the level reaches 5 or 6 ft. or so, after which the flooding near the Hwy. 1 bridge will recede.
Although the highway flooding will probably end by 9 or 10 PM, CalTrans and CHP may wait until daylight to reopen it.
Check the link below for official information about the highways:
On Hwy. 20 there is one-lane traffic near Whiskey Springs due to slide removal.
Staying home warm and dry is a good plan for today.
N.Wilson
Update as of 7:30 PM Sunday: The river rose more than 5 ft. between 4 PM and 6 PM and began flowing over the pavement at the low point near the intersection with Hwy. 1. The river began flowing over the sandbar about 5 PM in a wide but shallow area centered on Pinnacle Rock. The outflow is reducing the rate of rise of the river in the estuary, but the latest NWS Navarro River forecast now forecasts a 25.1 ft. crest at 8 PM. At that level there will be 2 ft. of water over parts of 128 between Flynn Cr. Rd. and the coast. That means the highway will be closed overnight and stay closed until CalTrans crews can clean up the mud and debris carried over the road. The official state website for highway conditions says 128 is still open at 7:30 PM, but that site usually lags a few hours behind real time. Here’s the site to check: https://roads.dot.ca.gov/?roadnumber=128&submit=Search