Snow has some benefit…. really!

Kids have always known that snow has value—a day off from school, sledding, a snowball fight. Adults, in contrast, tend to focus on the negatives, ranging from road conditions to shoveling out the driveway.

Yet if you look at snow from an environmental point of view, you may learn to appreciate the white stuff for its benefits to the landscape and to the water supply.

Delaware averages 20 ½ inches of snow a year. According to the Farmer's Almanac, the First State will get above-normal snowfall amounts this winter, which makes it even more important to look on the bright side of this natural winter precipitation.

The phrase “blanket of snow” is more than a visual description—it's accurate in terms of warmth. Snow is an excellent insulator for gardens and landscapes, protecting these natural areas and its animal inhabitants against low temperatures and battering winds, and lessening, to some extent, the extremes of temperature fluctuation to which the soil is subjected.

The extent to which snow protects depends on its depth. Generally, temperatures underneath a layer of snow increase about 2 degrees F for each inch of accumulation. Because the soil also gives off some heat, the temperature at the soil surface can be much warmer than the air temperature. One study done at -14 degrees F found the soil below a 9-inch deep snow registered a surface temperature of 28 degrees F!

Snow also provides needed moisture to many landscape plants, thus preventing plants from drying out during the cold months. Even dormant plants continue to lose moisture through transpiration as water evaporates through their branches. Evergreen plants, which keep their foliage throughout winter, are at even greater risk of injury from lack of moisture.

The water content of snow is more variable than most people realize. You may have heard the 10 to 1 ratio—10 inches of snow equals 1 inch of rain— which is commonly reported and repeated as a rule of thumb. This 10 to 1 formula works well when temperatures hover near the freezing mark, but the ratio depends on the temperature at the time the snow falls.

Ten inches of fresh snow can contain as little as 0.10 inches of water or as much as 5 inches, depending on crystal structure, wind speed and temperature, among other environmental factors. Fresh, undisturbed snow has a high percentage of trapped air within the lattice structure of accumulated snow crystals. Freshly fallen, uncompacted snow typically is 90 to 95 percent trapped air. Because the air can barely move, heat transfer is greatly reduced, thus slowing the flow of heat from the warm ground to the cold air above.

At higher temperatures, say a few degrees above freezing, snow is often heavy and laden with water. Then, the ratio might be more like 5 to 1, in which case 5 inches of snow will melt into 1 inch of liquid.

At lower temperatures, snow tends to be light and fluffy, and the ratio is often greater than 10 to 1. During the Great Delaware Blizzard of '96, when Wilmington saw 22 inches of snowfall, temperatures hovered in the low 20s. This snow ration was 1½ inches of water, or a 15 to 1 ratio.

As the snow melts, a number of environmental factors may be affected. A fast melt can cause flooding, especially in urban and developed areas covered in concrete. Rapid melting combined with overtaxed or clogged drain systems will send potentially pollutant runoff directly into streams and rivers. Rapid melt of snow with a high water content is exactly what happened in Delaware in the ‘96 Blizzard, causing destructive flooding. However, a slow snow melt means water trickles slowly into the earth, percolating through the aquifer, thus purifying water for our drinking supply.

The next time you see snow falling, don't dwell on what a mess your morning commute will be. Instead, try to remember that those flakes are protecting your landscape plants, your water supply and Delaware 's wildlife.