SANTA ROSA (CBS SF) — Santa Rosa city officials Sunday afternoon asked residents of parts of the hilly Fountaingrove area to be ready to evacuate because rain in the coming days may cause flooding, landslides and sinkholes.

The officials gathered with residents at 1 p.m. at the Finley Community Center at 2060 W. College Ave. to tell them that the wildfires last month destroyed some storm drainpipes leaving voids underground and causing at least one sinkhole.

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The officials said pipes at eight other locations burned, which could prompt more sinkholes as well as landslides and flooding during the coming storms.

Crews are investigating 20 other sites where pipes may have been affected by fire.

“The pipes caught fire and in some cases were destroyed for significant lengths of up to a few hundred feet,” Bennett Horenstein, director of Santa Rosa Water, said.

The first sinkhole was discovered Friday at the end of Newbury Court and had been repaired as of this evening, Adriane Mertens, a spokeswoman for the Santa Rosa Emergency Operations Center, said.

The sinkhole occurred when 250 feet of pipe was destroyed, causing a 4-foot diameter, 7-foot deep hole.

City officials have reopened the emergency operations center because of the potential for more damage and evacuations.

City crews will be monitoring the Fountaingrove area until they have identified and repaired all the damaged infrastructure.

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Six sections of the Fountaingrove neighborhood are at risk.

The identified areas have as few as 78 residents and as many as 200.

City crews are using television cameras, among other means, to identify the drainpipes that have burned.

Light rain is expected to start falling tonight in Santa Rosa, Jim Wallmann of the National Weather Service said.

Heavier rain will fall between 9 a.m. and 2 p.m. Monday. The storm could bring as much as an inch of rain to the hills. Up to a half an inch could fall in the valleys, Wallmann said.

The forecast calls for winds of 10 to 15 mph with gusts of up to 25 mph.

Tuesday is expected to be dry but rain is forecast to fall again Wednesday and Wednesday night. Up to three-quarters of an inch is expected in the valleys and up to an inch and a half in the hills.

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The heaviest rain will fall Wednesday afternoon into Wednesday evening, according to Wallmann.