Local officials are welcoming the cloudy skies and rainy days, but say it is too early to judge what it means for the region's water supply come summer.
The short-term impact of this week's rain was being felt Thursday evening on small streams and creeks, resulting in the National Weather Service issuing a flood advisory for eastern Stanislaus County.
Dry Creek spilled over its banks just north of Waterford on Thursday afternoon, and Merced public works employees were sandbagging a milelong stretch of Bear Creek as a precautionary measure.
The weather service issued a flood advisory until 4 p.m. today for possible rapid rises along small waterways, including Dry Creek from Waterford to Modesto.
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Shortly before 4 p.m. Thursday, local emergency services agencies reported to the weather service that Dry Creek's water was out of its banks where the creek intersects with the Oakdale- Waterford Highway.
Other area creeks in eastern Stanislaus County may see rapid rises and local flooding as moderate to heavy rain was expected to continue into today, according to the weather service.
In Merced County, Bear Creek Drive from Driftwood Drive to Crystal Springs Avenue was closed to traffic while it received layers of sandbags to buffer it from swiftly-moving Bear Creek. City of Merced spokesman Mike Conway said the sandbags were part of the city's effort to stay ahead of the rain.
Snow levels Thursday night ranged from 1,500 to 2,000 feet in the Sierra, according to the weather service. Snow accumulated in Columbia and around Sonora.
Snow levels were expected to gradually increase to 3,000 feet today and up to 4,000 feet by Saturday night.
The weather service issued a wind advisory from 4 a.m. to 4 p.m. today for the southern Sacramento and Northern San Joaquin valleys.
A southeast wind of 20 to 30 mph with gusts up to 45 mph was expected to blow through the region this morning, according to the weather service. The wind is expected to remain strong through this afternoon and weaken this evening.
Wind can make driving difficult, especially in high-profile vehicles. Trees and structures weakened by wind that pounded the region earlier this month may experience more damage.
Weekend storm possible
A stronger storm could move into the Northern San Joaquin Valley late Saturday through Sunday afternoon, bringing strong wind and heavy rain to the valley, according to the weather service. There is a possibility of heavy snowfall in the mountains.
Reservoirs, which depend on snowmelt, remain low. While the moisture is a good sign, a more telling measure will be available next week when state water officials conduct a manual snow survey, said Steve Boyd, assistant general manager of Turlock Irrigation District.
He judged the mood among water officials after the dry season last year: " 'Improving' is a great way to say it; another may be 'cautiously optimistic' with this last storm," he said.
Rain is forecast for the Modesto area through tonight and then again Saturday night through Sunday night. Snow is forecast into tonight in the high country.
The district's snow sensors suggest the watershed above Don Pedro Reservoir has a snow level 90 percent to 100 percent of normal. But, Boyd said, only the survey next week can estimate water content of that snow.
"The more water content there is, the more water ends up in the reservoir, and that's where we really get a good sense of what's up there."
Don Pedro, which also serves the Modesto Irrigation District, had a water level of 758.5 feet Thursday. That included 2.5 feet gained during the storm earlier this month, Boyd said.
That compares with a level of 795 feet this time last year, said MID spokeswoman Kate Hora.
"No one is saying the drought is over, and no one is saying it has come to an end as of yet," she said. "It is very early in the season."
January, she said, is an unpredictable month and often a poor predictor of the overall season.
"I could give you any number of examples where we had very wet Januaries but came out dry as a whole for the year," she said.
The MID has recorded 4.36 inches of rain for January at its Modesto headquarters. The historical average is 2.34 inches. The seasonal total for rainfall is 7.98 inches, compared with a historical average of 6.63.
Certainly the rain falling on the Northern San Joaquin Valley is helping recharge groundwater and the extent to which that rain continues determines the likelihood that irrigation districts will have to draw early from the reservoirs to water farms, Boyd said.
But there are enough unknowns to leave the water year a question, said Troylene Sayler, spokeswoman for the South San Joaquin Irrigation District.
"We're really anxious to hear about the snow survey, but the other tricky part is that while it might look good when we get those numbers, if it doesn't continue to snow at those elevations, the situation could change again."
"There have been times when we haven't gotten any good news from October through February, and then all of a sudden, March is a really wet month, and we have gotten 100 percent of our water needs met in one month," Sayler said. "The situation is very changeable. So agencies like ours are taking it day to day."