With snow and sub-freezing temperatures on the way, organizers of local extreme weather shelters are struggling to staff their sanctuaries.

Shelters located in three Yakima churches are likely to be full at the end of the week when bone-chilling temperatures -- the coldest of the season so far -- and a chance of snow are expected to roll into the region.

According to the National Weather Service, overnight lows on Saturday are expected to dip into the teens or single digits. Forecasters predict high temperatures Sunday and Monday only in the 20s.

Monday, there's even a chance of snowfall, the first of the season, "anywhere from a dusting to 4 or 5 inches," said G.K. Hepburn, a meteorologist with the National Weather Service in Pendleton, Ore.

"It's been kind of dry and sort of mild for this time of year," Hepburn said. "We're finally going to get a taste of winter."

Dave Hanson, the director of Yakima's extreme weather shelter program, worries he might have to turn people back out into the streets if he runs out of beds and volunteers. This weekend, he said, "We're probably going to see a higher number of people."

The extreme weather shelters, staffed by community volunteers, offer homeless men, women and children a place to sleep from approximately November to March, when it's typically 32 degrees or colder overnight.

Hanson, an assistant pastor at Vineyard Christian Fellowship of Yakima, predicts frigid temperatures on Saturday night and Sunday will draw in more people, stretching the shelters' staffing numbers.

Sunrise Outreach, a ministry at Vineyard Christian Fellowship, contracts with the Homeless Network of Yakima County to run the three shelters. The network represents about two dozen organizations that advocate for the homeless.

"We desperately need volunteers," said Hanson, who serves as executive director of Sunrise Outreach.

Earlier this year, he estimated he needed 250 volunteers to run the program, which is in its third year. With the recent opening of a third shelter -- and possibly another one later this winter -- he now estimates he needs 300.

So far, 160 volunteers have been trained. But "a lot of them are working for a short period of time, and we need them for a longer time commitment," Hanson said.

The shelters are in particular need of male volunteers to staff the two men's shelters at First Baptist and Englewood Christian churches. First Baptist has 16 beds; Englewood has 12 and the potential to expand to 20.

Hanson predicts the extra beds will be needed. In fact, he might even need to open a fourth shelter. But, he said, "I can't even think about that until we have more volunteers."

"It's the holidays. Now's the time we need them the most."

Last season, the shelters -- including the Vineyard, which has 12 beds for women and children -- served about 250 people. Only a few were turned away because shelters were full.

More than 1,000 people in Yakima County are homeless, according to a 2008 survey. Many advocates believe the actual number is probably three times that amount.

This year, Hanson plans to serve more people than last. But some have already been turned away.

"The last week in November, I was turning six men away every night. That's why I opened the third shelter, even though I don't have enough volunteers to make it easy," he said.

"We're at capacity now at First Baptist. I think by the end of the week, we'll be at capacity at Englewood."

Yakima's Extreme Weather Shelters

Hours: Open 6 p.m. to 6 a.m. daily.

Women and children: Vineyard Christian Fellowship of Yakima, 221 E. Martin Luther King Jr. Blvd., 12 beds.

Men: First Baptist Church, 515 E. Yakima Ave., 16 beds. Englewood Christian Church, 511 N. 44th Ave., 12 beds.

Volunteer training: 6:30 p.m. Monday at Vineyard Christian Fellowship.

Information: Dave Hanson, 453-2343.