NEW YORK - After making landfall in Mexico earlier Sunday, tropical storm Hilary started to unleash wind gusts and heavy rain across California, where officials have warned of potentially deadly floods.

Hilary's center is just a few hours from Southern California, but the state has been feeling the storm's effects since early Sunday and the rainfall totals are starting to add up, reported CNN.

"We are not used to this level of precipitation, generally. Certainly not in the middle of summer," San Diego Mayor Todd Gloria was quoted as saying on Sunday. He was worried about potential power outages from the wind as well as flooding. "We're not built for this kind of rainfall ... With what we're expecting, it may overwhelm us," he added.

Hilary had maximum sustained winds of 60 mph (97 kph) at roughly 2 p.m. local time (2100 GMT) and was about 115 miles south-southeast of San Diego, the National Hurricane Center said.

Forecasters said the storm was still expected to enter the history books as the first tropical storm to hit southern California in 84 years, bringing flash floods, mudslides, isolated tornadoes, high winds and power outages.

California Governor Gavin Newsom proclaimed a state of emergency, and officials had urged people to finish their preparations before sundown Saturday. It would be too late by Sunday, one expert said.

"The hurricane is the latest major climate disaster to wreak havoc across the US, Canada and Mexico," The Associated Press reported, adding that it could dump up to 10 inches (25 cm) -- a year's worth of rain for some areas -- in southern California and southern Nevada.