Sunday's snow across much of Minnesota was one small step toward drought relief.

Because the ground is still frost-free, much of the moisture held in the snow should melt directly into the thirsty soil.

Snow cover in the Twin Cities had already compacted to a 7-inch depth Wednesday, under a high temperature of 41. Thursday's high of 35 should begin to release some of the water into the ground, said assistant state climatologist Pete Boulay.

"It'll be a drop in the bucket compared to what we need," said Diane Cooper, hydrologist with the North Central River Forecast Center, which is part of the National Weather Service's Twin Cities office in Chanhassen.

But farmers and others were willing to take what they could get.

"It's going to be very helpful," said Doug Peterson, president of the Minnesota Farmers Union, who saw 15 inches of snow fall on his farm near Madison, 160 miles due west of the Twin Cities. "Across the growing region, moisture of any type is welcome."

The weekend snow fell over an area of Minnesota that's been in the U.S. Drought Monitor's "extreme" drought category for weeks. The Twin Cities is only about 3 percent short (0.98 inch) of its normal precipitation for the year, but that's largely due to an extremely wet spring. From mid-June through Nov. 30, the Twin Cities and much of southwestern Minnesota has received 7 to 10 inches less precipitation than normal.

Recovering from that deficit would require perhaps a record snow season, Cooper said.

"That's the downside of snow. It takes a lot of snow to recoup -- a lot of days with commutes like we've just had," she said.

But conditions are near-ideal for some recovery. Repeating snow -- more is forecast for the weekend -- will continue to insulate the ground, keeping it free of frost and allowing snowmelt to penetrate, Cooper said. Moisture at the surface will be available to spring seedlings. Moisture below that will help deeper roots. Beyond that, precipitation can recharge aquifers and rivers and lakes. And by storing water, unfrozen ground reduces the potential for spring flooding from later snows or rains.

Even as far north as Crosslake, north of Brainerd, where there was only about 3.5 inches of snow on the ground Wednesday, frost was only 4 inches deep, said Deb Griffith, head ranger at Crosslake Recreation Area. A cold and snow-free Minnesota winter can drive frost 60 inches deep across northern Minnesota, Cooper noted.

"This doesn't solve our drought problem, but it's kind of going the right way," Boulay said.

Bill McAuliffe • 612-673-7646