Wednesday, February 4, 2015

Winter's Resurgence and the Maine Event

Snowstorms have been in the news regularly the last week or so. First was the Northeast blizzard which left two three feet of snow across much of eastern New England. Then there was the storm this weekend which produced blizzard conditions in northeastern Illinois and northern Indiana, and dropped 12 to 18 inches of snow from Iowa through northern Illinois into northern Indiana and southern Michigan. As that storm marched east it compounded problems in the Northeast by laying down another 6 to 12 inches of snow from eastern New York across New England. Higher amounts, up to 18 inches, occurred in eastern Massachusetts to Downeast Maine.
Snowfall for the 72-hour period from 7:00 a.m. January 31 to 7:00 a.m. February 3, 2015

Many locations in the Midwest and Northeast doubled their season-to-date snowfall this week. Chicago piled up 19.3 inches of snow from January 31-February 2, making it the fifth largest snowstorm in Chicago's history. The largest snowstorm is 23.0 inches from the Big Snow of January 26-27, 1967. So far this week Chicago has measured 22.6 inches of new snow, and more fell today. The total for the season so far is 36.3 inches. The average for Chicago for the season is 38.0 inches.

Detroit, MI had been enjoying a fairly tame winter until this week as well. However, the big storm last weekend dumped 16.7 inches on Detroit with 18.4 inches in the last week. That brings their seasonal total to 35.8 inches. The average seasonal snowfall for Detroit is 44.1 inches.

Much of New England was just getting back to normal when the weekend storm brought more snow to the region. Boston picked up another 15.9 inches of snow, making it 42.5 inches for the week.

However, the most impressive and spectacular snowfalls occurred in Downeast Maine. Our CoCoRaHS observer at Eastport 1.5 SE (ME-WS-24) has measured 76.0 inches of snow since January 24! As of this morning the snow cover was 60.5 inches deep! This is far and away a record for a ten day period.

Daily snow fall and snow depth values for the CoCoRaHS station at Eastport, ME (ME-WS-24)
There was a U.S. Cooperative Network station in Eastport from 1895 to 2013, and the most snow recorded in a 10-day period at that location was "only" 37.5 inches. Other locations in Downeast Maine also tallied some impressive ten-day totals. Bangor had 44.5 inches, Machias, ME measured 62.1 inches (old record 35.5 inches in December 1964, records go back to 1893), and Robbinston, ME received 54.7 inches, breaking the records of 32.7 inches in March 1999 (records go back to 1994). You can view the individual storm maps for the entire season for Maine on the NWS Bangor web site. The average seasonal snowfall in the Eastport area is about 72 inches. The maximum snowfall since 1951 is 132.4 inches in Machias, ME in 1955-56 (there were five years missing in the 1980s).

Snow piled up in Eastport, ME. Photo by Wayne Tripp.
Wayne Tripp, the CoCoRaHS observer at ME-WS-24 (Eastport 1.5 SE), said that the last two weeks have been tiring. He's had to move his rain gauge to a new location because the normal spot is under a seven foot drift. "As you can imagine, measuring the snowfall has gotten quite challenging - between drifts of up to 10 feet from the blizzard, huge snowbanks from removing the snow and the pure challenge of getting away from the roads to do any measurements, have had to rely on common sense." Wayne said.  "I try to measure snow in many locations that I can access around the house - have found that there are some nicely sheltered sections where there is minimal drifting or blowing, and the deck (usually) is a good surface.  As the snow was piling up recently, it got progressively more difficult to find areas to measure - the latest storm with 18.1" had a great deal of drifting even on the deck.  I have resorted to slogging to a neighbors yard (they are summer folk) and taking a transect - almost like a geology task - through the snow.  Each storm has a very discrete layer, so I can dig into the yard and get a measurement for the most recent storm.  I may need to resort to snow shoes soon, though, as my stature is decidedly less than the current snow depth!"

Looking down the street toward the shoreline in Eastport. Campobello Island (Canada) is nearly obscured by the sea smoke. Photo by Wayne Tripp

Despite the regular sequence of winter storms the past two weeks, only 37.4 percent of the U.S. has snow cover as of this morning. Last year the figure was 61.2 percent.

Snow cover over the U.S. on February 4, 1014 (left) and February 4, 2015.
Maps from the NOAA/NWS National Operational Hydrologic Remote Sensing Center

The highest percentage this season so far was on January 4 when 54.1 percent of the U.S. had snow cover. On November 17 snow cover was 50.1 percent as a result of the unusually cold and snowy period the middle of that month. Note that the largest difference on these maps is the lack of snow in the western U.S. this season. The chart below shows the daily percentage of the U.S. covered by snow since November 1.
U.S. covered by snow as of February 4, 2015.

For the Northeast sector of the country, snow cover is 99.2 percent with an average depth of 20.3 inches


  1. Good work, and I appreciate the extra effort of Mr. Tripp. Just wondering, though: Where's the 0.8% of the Northeast sector NOT covered by snow?

    1. Pete, that's a good question, Clearly the map shows complete snow cover. I suspect it has something to do with the assimilation model NOHRSC uses. I'll see what I can find out.

  2. I checked with Tim Szeliga at the National Hydrologic Remote Sensing Center. Remember, the data used to produce these maps are "modeled" utilizing actual observations. Tim indicated that the Northway from Burlington VT and Plattsburgh NY and up to the Canadian border is snow-free in the model. There are also a few snow-free patches in central Massachusetts and New Hampshire. According to Tim, "...there seemed to be a halo of a few open pixels around Lake Champlain and along the Atlantic coastline. There may be snow on the beaches, but the effects of the warm water and downscaling the derived temperatures would extend inland a bit." Also, when the maps are produced masks are used to delineate land and water. These masks are more detailed than the 1 km square blocks for snow cover, so the resolution differences could contribute to that 0.8%.