SAN JOSE (CBS SF) – The Coyote Creek overwhelmed a large homeless encampment along its banks Tuesday morning, forcing as many as 20 people to climb into trees to escape the rapidly rising waters.

Authorities said they received a call at about 6:35 a.m. reporting people in trees near Lone Bluff Way and the Los Lagos Golf Course.

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San Jose Fire Department spokesman Mitch Matlow said the homeless residents of the encampment had been warned to leave the area because of the threat of rising waters as the Anderson Reservoir has overflowed.

The Anderson Reservoir overflow feeds into the Coyote Creek. For the first time in more than a decade, the reservior — swollen by weeks of rain has overflowed its banks.

Matlow said five people had been rescued with others calling for help from the swamped woods. He said a rescue helicopter had been sent away so rescue teams on boats could hear calls for help.

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“We were told there were 20 people in trees, but we don’t have an accurate count,” he said.

Matlow said the water-borne rescue teams were battling “rising waters filled with debris.”

It was the second time a swift water rescue teams had been dispatched to the area. On Monday, three people trapped by the rising waters in an area north of Tuesday’s rescue were pulled from an island in the middle of the creek.

The National Weather Service reported the creek was at 13.2 feet Tuesday morning – slightly below the major flooding stage of 14 feet.

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A flash flood warning was issued for the creek Monday evening through Friday morning as 3 1/2 inches of rain fell in the surrounding area.