HANOVER, N.H.—ERDC Cold Regions Research and Engineering Laboratory’s (CRREL) Steve Decato, a physical science technician, recently provided training at a local field site on the fundamentals of a successful snow pit so laboratory scientists could learn how to dig and characterize snow pits for their research.
Decato may be one of the lab’s foremost experts when it comes to digging in the snow pack. He has dug pits locally and internationally, including areas in Michigan, New England, Alaska, Canada, and as far away as the Svalbard Islands, Norway, for more than 25 years.
By taking a look at the snow’s profile, you can learn about the snow pack layers. Some use the information for avalanche safety precautions and others use the data to substantiate their research.
First, one must find a representative snow pack in which to dig a snow pit, while trying to keep a north face for keeping it at a stable, cold temperature. With the early spring temperatures and snow melt, this can be difficult.
“Keep your snow pit facing north or sun will rot it away,” said Decato. “Be conservative regarding how much digging you do; you do not want to compromise future snow pits.”
Decato described the snow he dug as melt freeze snow. After digging down to approximately 6 inches, he pointed to a darker, harder snow layer, which looked to be an ice lens at the base.
According to Dr. Susan Frankenstein, who participated in the training, the training site, during the previous week, had 4 inches of good snow, but with sun exposure and the warming temperatures, the ice had begun to melt or “rot.”
Decato confirmed, “This snowpack is on its way to rotting away.”
The snow pit kit, contained in a hard plastic box, included a notebook with waterproof paper, a waterproof pen, snow temperature probes, a black velvet-covered square for characterizing snow crystals, a ruler, a compass, and what looked like stainless steel slotted spatulas.
“On average I take 10 samples to get a good characterization and a range,” said Decato. “It is really important to take your time and record date, time, location, slope pitch, air temperature, compass aspect, wind, clouds and any other observations because you may need to depend on those later when looking at the data. A pit takes me about 45 minutes to dig, record observations, and take measurements; this type of work takes patience.”
Snow pits can be dug and characterized at night, although this is rare, to take advantage of the cold and low light. At times, the snow layer profile is much easier to see at night by digging a back lit pit and positioning a flashlight, so that the layers can be illuminated. However, typically, snow pits are worked during the day when temperatures tend to be warming and the snow changing.
“In the spring the earth’s heat wants to come to the surface and it becomes a losing proposition as the snow pack rots,” said Decato.
Snow pits may be considered “old school” science, but even today researchers look to this proven and valuable technique to provide ground truth for their research.