Anyone watching and listening to the first day of a storm that’s supposed to bring up to 10 inches of rain to foothill towns in the Mother Lode and up to 15 inches of rain in Yosemite Valley is entitled to ask “What’s the big deal so far?”

From Sonora to Jamestown, Moccasin and Chinese Camp this afternoon, the pitter-patter of light showers tip-tapped on people’s roofs and awnings at times Saturday. Intermittent showers sounded and looked nothing like a biblical deluge.

But forecasters warn people up and down the Central Sierra not to let their guard down. The main event is coming.

Johnnie Powell, a National Weather Service meteorologist in Sacramento, makes calls to check rain gauges regularly at Pinecrest, Calaveras Big Trees State Park, Groveland and Hetch Hetchy. He laughed when asked when the heaviest rains are expected for the Mother Lode.

“Overnight tonight and Sunday morning, the intensities will pick up,” Powell said. “The heaviest rain is coming Sunday mid-afternoon. The party hasn’t started yet. Check with me tomorrow this time. This is just the appetizer.”

Flood watches extended

The current storm system is expected to last into Monday and forecasters say there are two other systems in line behind it, expected to bring more rains Tuesday and Wednesday, and again later next week.

With that in mind, flood watches for Highway 49 towns including San Andreas, Copperopolis, Angels Camp, Columbia, Sonora and Jamestown are now extended out through Wednesday.

The current warm storm is described as an atmospheric river laden with tropical moisture and forecasters fear heavy rains on significant snowpack depths at high altitudes will unleash enough runoff to trigger the worst flooding in a decade or more in vulnerable locations in mountain and foothill towns.

Sonora can still expect 7.5 to 10 inches of rain between Saturday and Monday, and Yosemite Valley could get 10 to 15 inches in the same time period.

Snow levels rising

Snow levels started around 4,000 to 5,000 feet this morning in the Central Sierra, and they were expected to rise above 8,000 feet this evening. Some people bagged ski plans today because they believed there would be so much rain on recent snow.

Earlier this week, the Tuolumne County Office of Emergency Services reminded residents the current storm has the potential to cause flooding, mudslides and widespread power outages. They urged residents to reduce or refrain from driving altogether once the heavy rains begin.

Due to all the dead and dying trees still standing in local forests, OES staff also reminded people to remain aware of their surroundings, watch for falling limbs, woody debris and falling trees. Some trees may have power or communication lines attached to them. These trees and lines should not be approached or touched. Call Pacific Gas & Electric and stay away from the area. The PG&E power outage line is (800) 743-5002.

Flooding expected in Yosemite Valley

In Yosemite National Park, the Merced River flood forecast was updated just before 2 p.m. today and the high water mark is now predicted to reach 18 feet, more than the 16 feet forecast yesterday, and more than 5 feet less than January 1997.

Park administrators announced they were closing all roads into Yosemite Valley as of 5 p.m. Friday, and hundreds of visitors and lodging were told to leave. Earlier today, a mandatory evacuation notice was issued for all non-essential residents, employees and personnel to evacuate Yosemite Valley by 4 p.m. Saturday.

Park staff tweeted earlier today the Merced River is expected to reach flood stage, 10 feet, Sunday morning. The Merced could crest at 18 feet or more shortly after 2 p.m. Sunday.

Cicely Muldoon, acting deputy superintendent of the park, issued a statement today advising the valley closure applies to “all individuals who have not been identified as essential by park management, the Flood Incident Commander, the responsible management official of NPS Concessioners who have operations based in Yosemite Valley or other park partners with physical infrastructure in Yosemite Valley.”

The presence of individuals who have not been identified as essential is prohibited, Muldoon said. The closure area will be monitored to ensure compliance.

The closure includes Big Oak Flat Road south of Foresta Junction to its intersection with El Portal Road, Wawona Road north of Chinquapin to its intersection with Southside Drive, El Portal Road from the park boundary to Pohono Bridge, all roads on the floor of Yosemite Valley, Half Dome Village, the Majestic Yosemite Hotel, Yosemite Valley Lodge, Housekeeping Camp, Yellow Pine, all Yosemite Valley campgrounds, and all National Park Service and concessioner housing areas.

Other areas of the park that are said to be open, road conditions permitting, include Hetch Hetchy, Hodgdon Meadow, Crane Flat and Wawona.

Sand and sandbags

In Calaveras County, sand and sandbags were available at the Arnold Maintenance Yard, 1119 Linebaugh Road, Glencoe Maintenance Yard, 16151 Highway 26, the Jenny Lind Yard, 11558 Milton Road, Mountain Ranch Community Park, Murphys Fire Station at 37 Jones St., the Vista Del Lago Cul-de-sac near DuHamel Family Dentistry, 313 Vista Del Lago, and 891 Mountain Ranch Road in San Andreas.

In Tuolumne County, sand was available at the Tuolumne Road Yard, 18870 Birch Street, Jamestown Road Yard, 18188 7th Ave., the Big Oak Flat/Groveland Road Yard, 11240 Wards Ferry Road, Tuolumne City Fire, 18690 Main St., Tuolumne, and Columbia Airport, 10723 Airport Road. Sandbags were available at some hardware stores.