Guam residents were drenched for a second straight day Monday by heavy downpours from Typhoon Tingting, which was upgraded Monday from a tropical storm.

At Commander, Naval Forces Marianas, 6 inches of rain had fallen since Sunday morning, base spokeswoman Lt. Arwen Consaul said Monday afternoon. Some areas in the south received up to 20 inches.

Tingting — a pet name for young girls in Hong Kong — continued to move away from Guam on Monday, churning northwest at 9 mph. The rain wasn’t expected to let up any time soon.

“We’re expecting flood damage and another 10 inches in the next day or so,” Consaul said. No ships were damaged, but “a lot of trees have fallen over and there’s a lot of flooding on base.

“I’ve never seen anything like it. You look out your window and you can’t see anything because of the rain and wind.”

Only essential personnel were to report for work Tuesday at the Navy base, Consaul said, while nonessential personnel were on two-hour standby.

Most of the base, including the naval hospital, was operating on generators. The installation receives its electricity from Guam Power Authority. The Pacific Daily News reported Monday afternoon that there were power outages throughout the island. All of the south was without power. Consaul said Monday that power in base housing was turned back on after a 24-hour blackout.

Navy base residents were asked to conserve water due to the storm. Consaul said the rainfall stirs up sediment in the reservoir. When that happens, “we have to shut down our treatment plant and go to our reserves,” she said.

CNFM and Andersen Air Force Base to the north remained at Tropical Cyclone Condition of Readiness 4 as of Monday, base officials said.

As of 1 p.m. Monday, Tingting’s center was 230 miles north-northeast of Guam and 100 miles north-northeast of Saipan, according to the Pacific Daily News. Maximum sustained winds at the storm’s center were 75 mph, with gusts up to 90 mph.

“The main system will not affect Andersen,” said 2nd Lt. Genieve David, a base spokeswoman.

Andersen experienced 58-63 mph gusts Monday and sustained winds between 40 and 46 mph, David said.

Storm damage will be assessed by the 35th Civil Engineer Squadron in coming days, David said. The base received 12 inches of precipitation from Tingting, including 4 inches on Monday.

Members of Andersen’s Navy Helicopter Combat Support Squadron 5 assisted the U.S. Coast Guard on Guam in Monday’s search for a 19-year-old island resident swept out to sea earlier in the day near the Hilton Guam Resort and Spa in Tumon Bay, said Lee Putnam, a search-and-rescue specialist for U.S. Coast Guard Marianas Section Guam.

A hotel guest watching the waves from her fifth-floor balcony reported the incident. “She saw him bobbing in the surf for a while and then he disappeared,” Putnam said.

The man was still missing as of Monday afternoon.

Waves breaking on the reef Monday were 15 feet high, Putnam said.

Three women who went swimming off Saipan drowned Sunday after getting caught in a riptide, according to local news reports.