Major Long Duration Upslope Snow/High Wind Event
Saturday-Sunday January 2 - 3, 2010

A unique northerly to northwesterly terrain enhanced upslope storm produced extremely heavy snow accumulations throughout the state of Vermont with an all time record snowfall for a single storm @ Burlington, VT of 33.1". Upwards of two feet of snow was measured along many north facing slopes of the Green mountains in Vermont all the way down to the Bennington area where public observations indicated 24" of accumulation at North Bennington by the storm's conclusion late Sunday night January 3. Heavy snow also fell in Washington County, NY and in the higher elevations of Rensselaer and Columbia counties and to a lesser extent in northern Berkshire County, MA. Another hot zone of northwesterly upslope heavy terrain enhanced snow occurred in the higher elevations of the western Catskills and Schoharie County, with Schenevus in Otsego County checking in with 19", along with 15" at Richmondville, and Gilboa. A mere 1"-3" of snow in comparison, accumulated throughout the eastern Mohawk valley, Capital Region and much of the mid Hudson valley over the two day period amounting to nothing more than a nuisance while only twenty to thirty miles east or west, a major wind driven snow storm raged.

Set Up:
A strong and persistent negative NAO (north atlantic oscillation) pattern, which had established itself in December 2009, continued into the new year and was the main player in setting the stage for the long duration snow event in the Northeast. In a negative NAO pattern, a strong blocking high pressure system at the jet stream level develops over Greenland, with an associated strung out upper level trough over the north central Atlantic. When the jet is configured in this way a cold low pressure trough is forced to form over the eastern United States which often supports slow moving stormy conditions along the eastern seaboard, especially during periods when the block either repositions or re-establishes itself, which is what occurred from late on January 1 through early on January 4.

In this case, a broad surface low pressure system slowly developing hundreds of miles off of the southern New England coast on Friday January 1 became energized when a mid level low pressure trough, moving across the Northeast with patchy light snow and snow showers, jumped into the system during the overnight period. The arrival of the mid level low caused rapid intensification of the off shore storm through the day Saturday January 2. A track out to sea, sparing the Northeast of any snow, would have occurred had there not been that upstream block in the road. With the block in place, the rapidly intensifying coastal storm was forced to move to the north-northwest towards the Maine coast through Sunday January 3. Synoptic scale snow, or snow directly related to processes ongoing with the storm itself, initially impacted mainly eastern New England, with a moderate to locally heavy snowfall on Saturday. With the storm however, backing in towards the Maine coast, synoptic snow was able to track all the way around the center of circulation into northern New England, helping to produce the all time record 33.1" snowfall total at Burlington, VT. Moisture from the ocean storm also contributed to the processes that ultimately produced the 12"-24" of snowfall throughout many other areas in Vermont.

Local Impacts:
Snow across WRGB's twenty one county coverage area varied about as much as I have ever seen it vary over such short distances since I began working here in 1991. With the main storm remaining for the most part just out of range of eastern New York and western New England, only throwing some fairly weak batches of synoptic snow into the region, the prime mechanism for producing the areas of heavy snowfall that were observed had to come from something else. And that something else was a fairly complex local scale interaction of an existing very cold and moist atmosphere, which got colder through the event, the wind creating strong upslope flow over the local terrain, and the shear persistence of the snow over the two and half day period which resulted from the almost stationary nature of the off shore storm. (Upslope flow, where the air is forced to rise over a mountain, is a powerful mechanism for producing lift. And in a sufficiently moist atmosphere, that lift will create precipitation.)

The Lakes:
A substantial moisture boost from Lake Champlain, especially on Saturday, when there was a fairly deep northerly component to the wind just off the deck, appears to have substantially contributed to the greatly elevated snow totals observed in Washington, parts of Rensselaer and Columbia counties in NY as well as throughout Vermont and northern Berkshire County. Elevated snow totals in Otsego, Schoharie, southwest Albany, and western Greene counties resulted from a significant moisture boost, primarily on Sunday when the wind had more of a northwesterly component, from Lake Ontario. Had lake moisture not come into play, the excessive snow totals that were observed in these areas would not have occurred. Lighter snowfall amounts throughout the remainder of the region (1"-3" on average in the Capital Region and eastern Mohawk valley ) resulted largely from the periodic light bands of synoptic snow that backed into the region, much of it falling on Sunday January 3. The snowfall distribution map below, generated by CBS6 meteorologist Erik Thorgersen after a long analysis of regional snowfall reports, clearly depicts how terrain and lake moisture enhanced the snowfall in this event.

WeatherNet 6 Snowfall Distribution Map for the January 2-3 Long Duration Event

Storm total snowfall distribution for the January 2-3, 2010 Snow Event

WeatherNet 6/NWS Storm Total Snowfall Reports for the January 2-3, 2010 Event

Town County Snowfall Town County Snowfall
Albany (NWS) Albany 2.8" to 3.5" Potter Hollow Albany 10.0"
Altamont Albany 7.1" Knox Albany 5.5"
Coeymans Hollow Albany 4.0"      
Sharon, CT Litchfield 6.0" North Canaan, CT Litchfield 7.3"
Savoy, MA Berkshire 12.1" Jiminy Peak, MA Berkshire 12.0"
Lanesborough, MA Berkshire 7.0" Great Barrington, MA Berkshire 6.5"
Pittsfield, MA Berkshire 5.0" Adams, MA Berkshire 14.0"
North Chatham Columbia 15.3" Chatham Center Columbia 12.0"
Ghent Columbia 12.0" Hillsdale Columbia 11.0"
Ancramdale Columbia 3.2" to 7.5" Kinderhook Columbia 7.5"
Stuyvesant Falls Columbia 4.4" Livingston Columbia 4.0"
Taghkanic Columbia 3.8" Germantown Columbia 1.1"
Poughkeepsie Dutchess 2.8" Rhinebeck Dutchess 3.0"
Roxbury Delaware 6.7" Delhi Delaware 2.5"
Stratford Fulton 6.0" Broadalbin Fulton 3.8"
Gloversville Fulton 3.0" Peck Lake Fulton 2.3"
East Jewett Greene 16.0" Windham Greene 12.0"
Halcott Greene 8.0" Durham Greene 5.0"
Lexington Greene 4.5" Catskill Greene 1.2"

Indian Lake

Hamilton 5.0" Long Lake Hamilton 4.5"
Little Falls Herkimer 9.5" Dolgeville Herkimer 5.8"
Fort Plain Montgomery 3.5" Palatine Bridge Montgomery 3.3"
Glen Mongtomery 3.0" Fonda Montgomery 1.5"
Amsterdam Montgomery 1.8"      
Schenevus Otsego 19.0" Worcester Otsego 16.5"
Cherry Valley Otsego 9.0"      
Buskirk Rensselaer 16.0" Grafton Rensselaer 16.0"
Averill Park Rensselaer 11.0" Hoosick Falls Rensselaer 9.5"
Center Brunswick Rensselaer 9.3" Brunswick Rensselaer 7.0"
Schaghticoke Rensselaer 6.8"      
Gansevoort Saratoga 6.0" to 7.4" Saratoga Springs Saratoga 4.0" to 6.5"
Wilton Saratoga 6.4" Round Lake Saratoga 3.0"
Ballston Spa Saratoga 2.8" Malta Saratoga 2.5"
Milton Saratoga 2.0" Clifton Park (Oaks) Saratoga 1.5"
Scotia Schenectady 1.8" Schenectady Schenectady 1.0"
Niskayuna Schenectady 0.7"      
Gilboa Schoharie 15.0" Richmondville Schoharie 15.0"
Summit Schoharie 12.0" West Fulton Schoharie 10.0"
Fulton Schoharie 9.5" Schoharie Schoharie 7.5" to 8.0"
Esperance Schoharie 7.0" Cobleskill Schoharie 6.6"
Jefferson Schoharie 6.5" Conesville Schoharie 6.0"
Highmount Ulster 8.0" Phoenicia Ulster 3.7"
Esopus Ulster 1.3"      
Glens Falls Warren 6.4" Lake Luzerne Warren 3.5"
Queensbury Warren 3.2" to 3.4" Gore Mountain Warren 3.0"
Willard Mountain Washington 23.0" Salem Washington 10.5" to 16.4"
North Granville Washington 16.0" Cossayuna Washington 15.2"
Easton Washington 14.7" North Hebron Washington 12.0"
Hebron Washington 11.0" Whitehall Washington 7.3"
Middle Granville Washington 7.0"      
Woodford, VT Bennington 26.5" Bennington, VT Bennington 20.0"
Sunderland, VT Bennington 20.0" Landgrove, VT Bennington 19.5"
Pownal, VT Bennington 18.1" Danby, VT Rutland 13.5"
East Wallingford, VT Rutland 15.0" Rutland, VT Rutland 7.8"
Clarendon, VT Rutland 12.0"      

A tight pressure gradient developed on Saturday January 2 as the off shore storm rapidly intensified on its trek toward the Maine coast. A north to northwest gradient wind of 20-30 mph developed across the region on Saturday with gusts ranging from 40-45 mph during the day, increasing to occasional gusts to near 50 mph between 6pm and midnight. (Peak gust @ Albany of 51 mph) Considerable blowing and drifting snow occurred in those areas dealing with the heavy snow through the night with travel conditions, especially throughout Vermont, reported to have been treacherous. Temperatures also dropped into the single digits and low teens through the night creating a very light powdery snow which was easy to blow around leading to further reductions in visibility in the heavy snow zones. The storm began weakening on Sunday the 3rd with a resultant weakening of the pressure gradient allowing the winds to come down to between 15 and 25 mph on average.