Whose woods these are I think I know. His house is in the village though; He will not see me stopping here to watch his woods fill up with snow.”
~ Robert Lee Frost
As we head into a new year, the snowfall in Montana is likely to be one for the record books. It has been snowing non-stop for several days, with new record snowfalls in Billings, Kalispell and much of the northwest part of the state.
Fort Keogh, Montana holds the title for the largest snowflake in recorded history. On January 28, 1887, according to the Guinness Book of World Records, a snowflake the size of a milk pan, 15 inches wide and 8 inches thick, fell in the wilderness outpost. In 1951 villagers in the English town of Berkhamsted reported snowflakes the size of saucers, 13m - 5 inches across. As recently as 1971 a snowflake measuring 20 cm - 8 inches by 30 cm - 12 inches fell in Bratsk, Siberia.
The word “snowflake” is really a misnomer. Other than hail or sleet, most people call any type of frozen precipitation snow or snowflakes. Actually, meteorologists tell us that a snowflake means an assemblage of individual snow crystals that have remained fastened together during their fall.
Snowflakes form when the near-surface air temperatures are close to freezing. At around 32F the snow crystals are stickier and when they collide they adhere to one another more readily than at colder temperatures. When the surface air temperature is extremely cold, the snow crystals do not stick together and the precipitation that falls is mostly comprised of snow crystals.
Formed inside clouds from ice molecules, snow crystals are normally 0.5 to 5 millimeters or 0.02 to 0.20 inches in size. Snowflakes are bigger - typically about 10 mm - 0.4 inches across and often as big as 20 to 40 mm - 0.79 to 1.57 inches. As water vapor within the cloud gathers on the ice molecule, it spreads into a simple hexagonal prism. As more moisture gathers on the prism, branches sprout out to form more complex shapes. The humidity and temperature inside a cloud is constantly changing, sometimes within seconds. These constant fluctuations in cloud conditions change the size and shape of each individual snow crystal. The crystals stick together and become snowflakes.
Really large snowflakes often exceed 50 mm - 2 inches and are made up of an aggregate of hundreds of individual snow crystals. For record breaking snowflakes to form requires near perfect conditions. In addition to the ideal temperature required for the snow crystals to stick together and clump, large flakes usually only appear in windless conditions. If the wind is blowing, the flakes break apart as they fall.
In Montana we have a lot of snowstorms. This means just about any storm marked by high winds and heavy snowfall. A blizzard or “whiteout” is another story. A blizzard is considered a storm with strong winds (over 35 mph) or a storm marked by falling or drifting snow in the air to reduce visibility to less than a quarter of a mile for an extended period of time. “All blizzards are snowstorms, but not all snowstorms are blizzards.”
"April 25-26, 1969. A late season storm brought a drastic change in weather to eastern Montana. A day after numerous stations registered their highest temperature for the month (many in the 80s), a cold front swept through Montana bringing blizzard conditions to much of the eastern half of the state. Temperatures fell more than 50 degrees in 24 hours with wind chill readings well below zero for nearly 48 hours.
Snowfall amounts of over 1 foot were widespread with higher amounts including a 32 inch tally reported near Sonnette. Wind whipped the fresh snow into drifts reported to be over 20 feet high in places. Power and phone lines were knocked out. Utility lines downed over a 12 county area resulted in losses of nearly $2 million (1998 dollars). Some residents of southeastern Montana were without power for two weeks and without telephone service for over a month. Over 100,000 sheep, horses and cattle were lost with cost in today's dollars tallying well over $10 million.” - National Weather Service
Winter Weather In Montana ~ Courtesy: BigSkyFishing.com
“Winter sees some extremes in Montana weather. During the winter, it is very common for the areas east of the Continental Divide to be in the deep-freeze of below zero temperatures while over in Missoula and Kalispell the temperature can be fifty degrees warmer – and without a wind chill to boot.
As mentioned earlier, this occurs due to the inability of most cold air masses to make their way over the Continental Divide. A couple of times each winter, though, the cold air is deep enough (high enough) to force its way through the mountain passes along the Continental Divide – sneaking through places like Logan Pass, Marias Pass, Rogers Pass and other low elevation passes. When this happens, western Montana – particularly NW Montana – can become just as cold – if not colder – than what is found to the east. Moreover, when this happens, the cold air has a nasty tendency to hang around for quite a long time. This is due to the peculiar topography of NW Montana – the huge valleys and tall mountains frequently trap the cold air – preventing it from being shoved out.
Western Montana during the winter receives much more snow, generally, than areas in eastern Montana. However, all areas of Montana can be hit hard by deep snows. Eastern Montana, along with the occasional deep snow, also suffers from the curse of seemingly always blowing snow.
Not surprisingly, eastern Montana also is much windier during the winter than is found in western Montana – just like during the summer months. This wind, besides making the wind chill plummet, also has a nasty tendency to blow the snow that does fall in eastern Montana all over the place. Huge drifts frequently form behind houses, barns, small hills and behind anything else that the wind can’t blow away. Snow fences along eastern Montana highways, which help to capture snow and prevent it from blowing onto the highway, are also a common sight.
How much snow falls in Montana changes, often dramatically, from year to year. The tall mountains in Montana – even those found in the eastern part of the state – often receive very substantial snow falls – generally ending the year with well over 100 inches of snowpack (snowpack = packed snow depth, not how much snow actually fell during the year. To create a 100 inch snowpack by early April usually requires well over 250 inches of snowfall during the course of the winter).
By contrast, the lower valleys in western Montana tend to avoid the deep snow that is found in the mountains. The mountains tend to draw away the moisture of big storms, leaving lighter snowfalls for the low elevation valleys. Generally, most lower valley locations in western Montana tend not to receive more than 50-70 inches of snow a year.”