BETHEL – Crusty snow crunched noisily under snowshoe-shod boots as Maine wildlife biologist Chuck Hulsey tromped uphill Tuesday afternoon on the side of Mount Will about a quarter mile off Route 2.

Carrying an old wooden-handled spade and a yardstick, Hulsey was headed for a deer-wintering yard in a stand of hemlocks to measure snow depth and snow conditions. The measurements are used to determine how many any-deer permits will be made available to hunters in next fall’s season.

“It’s very interesting how much snow changes week to week,” said Hulsey, who is headquartered in Strong.

Measuring snow and temperatures is something that Maine wildlife biologists do every week during the winter at up to 30 stations in deer yards.

By gathering data on how far deer sink into snow when walking or running atop it, the condition of the snow, and temperatures, a winter severity index can be established.

Severity is measured in percentiles from 0 into the 90s as below average or mild (closer to 0), average, and above average or bad.

“If it’s an above-average winter and deer numbers are below the population objective, we’ll give out fewer permits,” Hulsey said. “If it’s a below-average winter, and they’re below population objectives, we may give out the same number of permits as last year and put the extra toward herd growth. We have times south of here where the population will be above normal and it’s a mild winter, so we’ll give out more permits.”

On Tuesday following one deer’s tracks, Hulsey measured leg-sinking depths of 4, 6, 7 and 8 inches in 10 tracks. The snow was 22 inches deep here. Average depths in the area ranged from 25 to 32 inches.

“I don’t think ice storms, per se, really have any effect on deer. The bigger effect is the amount of snow and periods of thawing and refreezing. If we had a winter with a lot of powder snow and no thawing, it would be hard on deer. When you have thawing, it creates layers and these layers are supporting deer.

“A few weeks ago, there was a thawing that caused the snow profile to go from something they sank in, to hard-packed loose granular in which they didn’t sink. Layering of snow affects how much they sink. If there is a thick ice crust atop the powder, it can cut their feet,” he said.

Despite the past few ice storms and Monday’s all-day rainfall, at one stop there was only half an inch of ice atop 8 inches of loose granular. That was layered atop a 3-inch-thick crust capping another 8 inches atop bare ground. In addition to open areas, Hulsey measures snow under hardwoods and softwoods.

“Every day costs a deer a certain number of calories on which to get by. In the winter, they live off their calories from food stored in their bodies, because of the food available, it’s not easy to get to and it’s not good quality, so they survive by finding good cover and try not to use much calories,” Hulsey said.

Trees that provide the best protection from the elements but are not good food sources include stands of cedar, hemlock, spruce and fir.

In a softwood stand, there is 40 to 50 percent less snow and cold than there is in hardwood stands due to leaf drop.

“If we get no rain for the next four weeks, these deer will be sinking farther. That’s why I always like to see rain in March. It makes it easier for deer on snow. I think that up to now, they’ve been OK, but a lot will depend on the last six weeks. We’re on track for averages, because … we haven’t been below zero much or had that long extensive bitter cold,” he said.