And because “there’s no substitute for in-person coat drives,” Ms. Amodio said, her charity has come up with creative ways to stage them. Last month, a school in Atlanta held a coat drive during morning drop off. Masked volunteers collected more than 400 coats through rolled-down windows.

Food banks are also experiencing surging demand. “Food insecurity in the United States is at a level that arguably we have not seen since the Great Depression,” said Katie Fitzgerald, the chief operating officer of Feeding America, a nationwide network of more than 200 food banks.

City Harvest, which distributes excess food in New York City, said that since March it had distributed more than 3.4 million pounds of food to more than 80,000 families at the nine mobile markets it operates throughout the five boroughs. That’s compared with two million pounds of food to 46,000 families over the same period last year. The markets operate every two weeks at each location.

City Harvest has stopped its choose-your-own style of distributing food at the markets during the pandemic and instead bags and boxes food in its warehouse. And volunteers can still help out while staying socially distant.

“We literally push the box or bag across the table and the individual goes on their way,” said Ryan VanMeter, the associate director of major gifts for City Harvest. “The thing I say to people who volunteer at our mobile markets is you’re going to feel all the blessings. But, yes, we are trying to minimize the interaction.”

But most critical right now, Mr. VanMeter said, is financial donations.

A recent study by a Fidelity Charitable, the nation’s largest grantmaker, found that two in three volunteers decreased or stopped contributing their time because of the pandemic. In its own survey, VolunteerMatch found that more people currently viewed Covid-19 as a barrier to volunteering than at the beginning of the pandemic, even though “we expected it to be the opposite,” Ms. Plato said.

Part of the reason for the volunteer shortage is that many volunteers are older people — the population most at risk for the coronavirus. But there are ways to donate your time and stay safe.