MANILA, Philippines (AP) — Forecasters sounded alarms over a new storm headed for the Philippines Wednesday, even as workers repaired seawalls demolished by a typhoon that killed at least 21 people and left scores stranded in swamped communities.

Typhoon Nesat also left 35 people missing and brought some of downtown Manila’s worst flooding in decades before blowing out of the northern Philippines early Wednesday (28) toward southern China with winds of 75 mph (120 kph).

Floodwaters were receding in most places, but many low-lying communities in the north remained in crisis.

Mayor Santiago Austria of the rice-farming town of Jaen in Nueva Ecija province appealed to the government for help, saying many people in his community of 63,000 needed to be rescued but that officials there had only four rescue boats.

“Many people here are still on top of their houses. We don’t have enough boats to reach them and hand them food,” Austria said.

Civil Defense Office chief Benito Ramos said army troops were on their way to assist Jaen.

The town of Obando, north of Manila, remained under waist-high water and officials had not yet been able to check on reports of houses swept away on two nearby islands where thousands of residents live, Mayor Orencio Gabriel said.

In all, 320,000 people were affected by the storm, with 73,000 in evacuation centers and about 100 still stranded, officials said.

Meanwhile, a fresh tropical storm was brewing in the Pacific, government forecaster Bobby Javier said, adding that it already had sustained winds of 52 mph (85 kph) and gusts up to 62 mph (100 kph) and was expected to strengthen significantly before hitting major parts of the country in the next few days.

Ramos said disaster agencies were being kept on full alert because of the new storm.

In Manila, hundreds of workers used cranes to lay sandbags where parts of a downtown seawall were ripped off by the typhoon’s huge waves and fierce winds. Residents made repairs to nearly 5,000 houses damaged in the storm.

Scavengers rummaged through household items carried by the floodwaters — footwear, a basketball, a child’s school bag, a hunter’s hat. Mar Depas, 28, said he collected about a dozen fairly new leather shoes and sandals but was disappointed that they didn’t match.

“I can’t find their pairs. They’re useless,” Depas said. “I came late … most of the better recyclable stuff is gone.”

Typhoon Nesat had unleashed torrents of floodwaters Tuesday that swamped Manila’s downtown areas, rapidly engulfing hotels, a hospital, the U.S. Embassy, business offices and several blocks of residential areas in waist-deep floodwaters.

Power was gradually restored Wednesday to Manila’s downtown area, which strewn with trash and fallen bamboo pieces washed ashore by storm surges. City trains resumed operations.