Heavy overnight rain falling on the Soberanes Fire burn scar has pushed the Big Sur River Gauge over the 10 foot level that is considered flood stage. The current level (at 6:00 am) is 10.48 feet. This translates to a flow of 4,860 cubic feet per second; essentially matching the 4,900 cfs peak flow of 2012 (which did not result in serious flood damage). The highest flow recorded at the Big Sur River Gauge, following the Marble Cone Fire in 1978, was 10,700 cfs.
The Big Sur River, with its smaller watershed, reacts to rain more quickly than the larger coastal streams. The Carmel River at Rosie’s Bridge is at 1,170 cfs and rising (peak flow there was 16,000 cfs in 1995).
The Arroyo Seco River Gauge is still only showing 161 cfs, but with some portions of its watershed receiving over 7 inches of overnight rain, the water will be rising quickly this morning.
The parched San Antonio River, which only began flowing past the gauge site on December 31, has only risen to 37 cfs… so far.
The Nacimiento River is at 4,350 cfs, an inconsequential amount for a stream that sometimes produces flows in excess of 50,000 cfs.
7:00 am Update: The Big Sur River is now above its 2012 peak; at 4,950 cfs (10.54 feet). The Arroyo Seco is at 1,140 cfs.
7:30 am Update: The Big Sur River has begun to drop. It’s currently at 4,720 cfs (10.38 feet). The Carmel River is up to 1,790 cfs. The Arroyo Seco is up to 1,990 cfs. The Nacimiento is up to 5,540 cfs.
9:30 am Update: The Big Sur River, at 9.95 feet (4,130 cfs), is no longer above flood stage. The Carmel River is at 2,630 cfs. The Arroyo Seco River has jumped to 7,560 cfs. The San Antonio River is barely changed at 39 cfs; and the Nacimiento now has the greatest flow, with 7,800 cfs. Some of the wettest spots along the Coast Ridge have received over 10 inches of rain since this storm began.
1:30 pm Update: The peaks have now passed on the local streams. It looks like the Nacimiento and Arroyo Seco rivers got up into the neighborhood of 12,000 cfs, or so, and the Carmel to around 2,700 cfs. The San Antonio, which must be dumping a lot of water into its bone dry aquifer, is still only pushing 41 cfs past the gauge.
With an even wetter storm forecast for this weekend, it would be prudent for those who live near streams to prepare for debris flows and the possibility of record, or near record, water levels.