Gabi Turnbull recalls talking on the phone in early April with her friend Daniel Goldberg about surfing.

The conversation shifted to something very different, and now, less than two months later, Goldberg is in California riding a monster wave and Turnbull anticipates one here on Oahu.

Goldberg’s father, an emergency room physician, is on the front lines fighting COVID-19, and Daniel wanted to help in some way, too. He came up with an idea: Could he and his friends do grocery shopping and delivery for older people and others who are vulnerable? That was in March, and it wasn’t long before Goldberg’s idea turned into a network, Zoomers to Boomers, that in these coronavirus times has gone, well, viral.

“He told me what he was doing,” said Turnbull. “And he said, ‘Would you like to start a branch?’ I was like, ‘Heck yeah, I will.’”

It’s something others are doing in many places; the difference is that ZTB is staffed almost completely by teen­agers, more than 300 at last count, in 26 cities and towns.

Turnbull, 16, and Goldberg, 17, are in most ways typical high school students. Their main bond used to be water polo, and mutual friends in Santa Barbara, Calif., where Goldberg lives. Turnbull also lived there, before her family moved to Manoa a few years ago.

Since that phone call last month, Turnbull, a sophomore at Mid-Pacific, has recruited about 20 volunteers, each handling two to four deliveries a week.

“We’re spread out all over the island,” she said. “That’s good, no one has to drive too far, and we can get people their groceries pretty fast.”

It’s an easy system: Answer a few questions online, including what you want to buy and from where. Turnbull confirms the order and assigns a driver in the area. The recipient pays for the groceries on delivery with cash, a check or via Venmo. There is no delivery fee.

The goal is to help folks who have no one to shop for them. ZTB volunteers don’t even charge for gas, and discourage tipping. If a recipient insists on giving them some money, it goes into a fund for people who can’t afford food.

The service became so popular so quickly in Santa Barbara that for a while Goldberg didn’t have enough volunteers to handle demand — nor enough hours in the day to run the organization.

“There were 14- to 15-hour days, it went three weeks like that,” said Goldberg, who still had schoolwork to do. “I’d be in a (online) meeting and conk out.”

But after changing the service to make deliveries in two days instead of one, things became more manageable. He also built a leadership team of several vice presidents — like him, all are high school students.

A lawyer friend of Goldberg’s father helped set up some aspects of the nonprofit, but otherwise adult involvement is minimal; the maximum age for drivers is 30.

But Turnbull said she is very grateful for a big assist from her mother, Leslie, who accompanies her on all her deliveries. The teen has a learner’s permit, but driver’s license tests aren’t being done now.

She sees this volunteer effort as her contribution toward fighting a common enemy.

“If we can help 20 people who need the help, and it helps keep everyone healthy, that makes us feel better,” she said. “All we’re doing is getting people their groceries.”

To sign up for grocery delivery or to volunteer as a driver, go to zoomerstoboomers.com/honolulu.