This is the reason, this is from the NWS, Monterey this morning:
HIGHWAY 1 ON THE BIG SUR COAST TO CLOSE TUESDAY IN SUPPORT OF MONTEREY COUNTY EVACUATION EFFORTS
MONTEREY and SAN LUIS OBISPO COUNTIES – Highway 1 on the Big Sur Coast will be closed between Ragged Point in San Luis Obispo County and Deetjen’s Big Sur Inn in Monterey County (44.6 miles) beginning Tuesday Jan. 26 at 5 pm.
This closure on Highway 1 is expected to remain in effect until Thursday, Jan. 28. Assessments will take place, during daylight hours and when safe to do so, prior to reopening of the highway.
Monterey County has issued an Evacuation Warning for areas downslope of the Dolan Fire burn scar where this storm brings an increased likelihood of debris flows.
Caltrans is working with local agencies to minimize travel into Big Sur to allow residents and businesses to evacuate in the safest conditions possible.
This evacuation closure of Highway 1 comes at the request of the California Highway Patrol and in support of Monterey County’s Evacuation Warning.
Ragged Point is located 1.45 miles south of the SLO/Monterey County line:
Deetjen’s Big Sur Inn is located in Monterey County at Post Mile 42.1:
Barricades, cones, as well as message and directional signs will be in place at both ends of the closure to alert motorists traveling in the area.
First off, I haven’t heard from Cal Trans on where they are closing highway 1, yet, but will add it right up at top of this post when I do. Secondly, this bull’s-eye on Big Sur is eye-popping, mouth-opening crazy. Some reports are that it will be sticking around for 20 hours or so, which is why rain amounts are so astronomical. Another report I read this am is that it is expected to arrive tonight, around midnight.
From Daniel Swain: “Then, on Wednesday, the #AtmosphericRiver/associated cold frontal rainband will likely stall along Central Coast (near border of Monterey/SLO counties). High-res models are suggesting potential for extreme 48hr rainfall accums, & very high flood/mudslide risk there.”
“The Hwy corridor and Big Sur, as well as the Dolan/River Fire footprints, appear to be at very high risk in this scenario. Other models aren’t quite as aggressive with rainfall totals here, but still suggest a high likelihood of 10-15 inches.”
PLEASE NOTE THAT THE MAXIMUM LISTED AT THE UPPER RIGHT CORNER IS 23.3 INCH.