MAJOR SNOW STORM Tuesday-Wednesday Morning February 23-24

An extremely heavy and wet snow blanketed eastern New York and western New England from Tuesday morning through the early afternoon on Wednesday February 23-24. Widespread major accumulations of 12"-17" occurred throughout the heart of the region with up to 29" reported in the highest elevations of the Helderbergs and southern Green mountains in VT. By Wednesday morning, when the bulk of the accumulation had occurred, the weight of the snow brought enough tree branches down on power lines that 34,000 National Grid customers lost power in the greater Capital Region with 70,000 central Hudson customers out in the mid and lower Hudson valley and eastern Catskills with power outages lingering through Thursday February 25. Several roof collapses were also reported with a number of barns coming down due to the extreme weight of the snow on the roofs.

Collapsed Barn from the weight of the snow on Sawmill Hill Road, Stillwater, NY, Saratoga County
Wednesday February 24, 2010
Photograph by CBS6 viewer: Barbara Raymond

Collapsed Barn due to the weight of the snow on Sawmill Hill Road in the Town of Stillwater, Saratoga County, February 24, 2010  

Initially, light snow fell through the morning with small scale narrow bands of moderate to heavy snow developing in the Hudson Valley and western New England during the afternoon. 1"-2" per hour snowfall rates occurred in the heavy snow bands by the mid afternoon with snowflakes up to the size of half dollars at times. Temperatures hovered near or slightly above freezing through the event yielding about as wet a snow as possible with snow to water ratios of 5:1 or 6:1, meaning an inch of liquid precipitation would produce 5"-6" of snow. (A typical snow to water ratio is 10:1) A steady state pattern set up through the night where multiple small scale snow bands developed over eastern New York, tracked west into the Catskills, eastern Mohawk valley, and southern Adirondacks, and then weakened. Between the heavy snow bands, much lighter snow fell mixed at times with drizzle or freezing drizzle. The entire heavy snow zone was narrow extending from the Catskills through the Hudson valley and into Berkshire County, MA and throughout Vermont. East or west of this zone, much lighter snowfall accumulations occurred. The graphic below is the WeatherNet 6 observed snowfall distribution map for the event illustrating the fairly small zone of heaviest snowfall centered on the Capital Region.

Click here for storm radar images

Click here for the WeatherNet 6 Observed Snowfall Distribution Map for This Storm

Set Up:
Strong jet stream blocking (negative NAO, north Atlantic Oscillation, pattern) coupled with a potent mid level trough and significant tropical moisture feed, originating over the Pacific ocean and Gulf of Mexico, teamed up to produce this major snow event. The blocking pattern at high latitudes over Greenland forced the development of a large upper level low pressure trough over the Midwest. Ejecting from the developing large scale trough, was a smaller scale trough that shot up into the Northeast through Tuesday and Tuesday night. The small scale upper trough triggered coastal low pressure development well east of Virginia which established a narrow but deep moisture feed directly into eastern New York and western New England. The surface low pressure system itself was quite weak as it moved north to a position south of New England, then weakening further, on Wednesday. The relatively slow motion of all the features and a highly favorable thermal profile over the region created the necessary environment for small scale heavy snow bands to develop over eastern New York and western New England over a prolonged period of time from Tuesday afternoon through Wednesday morning, yielding the excessive snow accumulations.

The pattern broke down through Wednesday morning as the small scale upper level trough moved northeast of the region and the surface low weakened south of New England. This process allowed the snow to quickly wind down, ending as patchy light rain or drizzle.

WeatherNet 6 Storm Total Snowfall Reports for the February 23-24, 2010 Event

Town

County Snowfall

Town

County Snowfall

Albany (NWS)

Albany 12.4" Cohoes Albany 13.0"
Latham Albany 13.5" Knox Albany 19.5"
Westerlo Albany 26.0" Feura Bush Albany 13.0"

East Berne

Albany 32.3" Green Island Albany 14.5"
Medusa Albany 23.0" Colonie Albany 13.5"
Watervliet Albany 13.0" Voorheesville Albany 14.0"
Potter Hollow Albany 25.0"      
           
Pittsfield, MA Berkshire 20.0" Alford, MA Berkshire 10.0"
Savoy, MA Berkshire 29.0" Lanesborough, MA Berkshire 16.0"
Sharon, CT Litchfield 8.0"      
           
Chatham Center Columbia 18.0" Taghkanic Columbia 12.7"
North Chatham Columbia 17.8" Livingston Columbia 12.0"
Craryville Columbia 12.5" Kinderhook Columbia 14.0"
Ancramdale Columbia 6.8"      
           
Poughkeepsie Dutchess 7.3" Rhinebeck Dutchess 11.5"
La Grange Dutchess 9.8" Red Hook Dutchess 9.5"
           
Arkville Delaware 10.0" to 13.3" Margaretville Delaware 13.0"
           
Northville Fulton 10.0" Gloversville Fulton 6.0"
Caroga Lake Fulton 4.0" Broadalbin Fulton 10.0"
Perth Fulton 12.5"      
           
Athens Greene 8.5" Catskill Greene 8.1"
Spruceton Greene 17.0" Durham Greene 20.0"

Round Top

Greene 9.5" Climax Greene 15.0"
Lexington Greene 18.0" Halcott Greene 16.0"
South Cairo Greene 13.0" Cairo Greene 16.0"
Ashland Greene 17.0" Greenville Greene 26.5"
           
Wells Hamilton 11.8" Indian Lake Hamilton 6.0"
Hope Falls Hamilton 11.3" Speculator Hamilton 12.0"
Long Lake Hamilton 1.5"      
           
Hessville Montgomery 8.0" Fonda Montgomery 7.5"
Amsterdam Montgomery 9.5" to 13.0" Glen Montgomery 10.5"
Fort Plain Montgomery 4.0" Stone Ridge Montgomery 4.0"
Palatine Bridge Montgomery 8.5"      
           
Worcester Otsego 10.0" Maryland Otsego 7.5"
East Worcester Otsego 7.5" Oneonta Otsego 4.0"
Cherry Valley Otsego 9.5"      
           
Center Brunswick Rensselaer 10.5" Speigletown Rensselaer 12.0"
Brunswick Rensselaer 12.0" Stephentown Rensselaer 15.5"
Schaghticoke Rensselaer 17.0" Taborton Rensselaer 22.0"
West Sand Lake Rensselaer 16.5"      
           
Porter Corners Saratoga 20.0" Providence Saratoga 18.0"
Charlton Saratoga 15.0" Saratoga Springs Saratoga 10.4" to 13.0"
Milton Saratoga 13.0" Burnt Hills Saratoga 15.0"
Clifton Park (Oaks) Saratoga 12.0" Ballston Spa Saratoga 13.0"
Gansevoort Saratoga 11.0" Corinth Saratoga 19.0"
Wilton Saratoga 14.5"      
           
Schenectady Schenectady 15.0" to 18.0" Scotia Schenectady 12.0"
Delanson Schenectady 18.0" Duanesburg Schenectady 18.0"
Niskayuna Schenectady 15.5" Glenville Schenectady 14.0"
           
Jefferson Schoharie 17.0" Richmondville Schoharie 9.0"
Esperance Schoharie 16.0" Huntersland Schoharie 15.0"
Schoharie Schoharie 14.0" Seward Schoharie 10.0"
Charlotteville Schoharie 14.5" Sloansville Schoharie 13.0"
Fulton Schoharie 18.0"      
           
Whiteport Ulster 5.5" Phoenicia Ulster 18.5"
Kingston Ulster 5.7" Saugerties Ulster 3.3"
Esopus Ulster 2.5" West Shokan Ulster 13.0"
           
Lake Luzerne Warren 22.0" Brant Lake Warren 21.0"
Queensbury Warren 12.7" Warrensburg Warren 20.0"
Glens Falls Warren 10.5"      
           
Salem Washington 6.0" Granville Washington 14.0"
Whitehall Washington 12.5" Cossayuna Washington 22.0"
           
Landgrove, VT Bennington 29.0" Woodford, VT Bennington 30.0"
No. Bennington, VT Bennington 7.0" Pownal, VT Bennington 9.7"
Danby, VT Rutland 17.0" West Rutland, VT Rutland 11.0"

The Second Storm
MAJOR LONG DURATION STORM: ( Excessive Snow, Heavy Rain, Localized High Wind)
Thursday-Sunday February 25-28, 2010

Click Here for the WeatherNet 6 Snowfall Distribution Map and Table of Reported Snowfall Amounts for the Period Thursday Through Noon Friday
(The map does not represent the Four Day Event Total)


Click Here for the Reported Four Day Snowfall Totals from Thursday February 25 to Sunday February 28, 2010

Click Here for the Combined Multi-Storm Snow Totals for the Tuesday Through Sunday Period, February 23-28, 2010

Click Here for RainFall/Storm Total Liquid Equivalent Precipitation 

Click Here for Radar Images 

Click Here for Photographs

It was a back to back blockbuster winter blast as another massive snowfall hit the Catskill region resulting in combined storm totals from Monday night February 22 through Sunday February 28 ranging up to an astonishing three to five feet in the higher elevations of eastern Delaware, eastern Otsego, much of Schoharie, western Greene, and western Ulster counties as well as the higher elevations in southern Bennington and northern Berkshire counties in western New England. And this second massive hit came with hardly a twelve hour break from when snow from the first onslaught (widespread 12"-17" accumulations) ended during the morning of the 24th.

This storm was the most powerful (meteorologically) to strike the Northeast since the April 15-16 2007 monster Nor'easter, with that storm's barometric pressure dropping to 968mb at its peak, down into where category 2 Hurricane's typically fall. The storm on this day had a central pressure at its peak intensity down to 972 mb just about as low. Both excessive snow and torrential rain occurred, with the sharp rain-snow line hovering just west of the Hudson river through almost the entire duration of the first phase of the event from Thursday morning through the pre-dawn hours on Friday. West of the line, excessive snow fell through early Friday morning, ranging from 17"-30" on average in the hardest hit areas of the Catskill region, much of central and southern New York, and Northeast Pennsylvania. Snowfall accumulations of 8 "-12" were common into the New York City area along with much of east central and southern Pennsylvania including Philadelphia and much of New Jersey. Well over a million utility customers in and around New Jersey and New York City were reported to have lost power due to the heavy wet nature of the snow bringing huge numbers of trees and utility lines down. East of the line, it was a driving rain, with amounts ranging from one to two and half inches on average in the Hudson valley and western New England. Widespread minor urban and poor drainage flooding occurred as most storm drains were clogged by the heavy snowfall only twelve to eighteen hours earlier. 55 mph to 65 mph wind gusts over the eastern New England shoreline produced widespread tree and power line damage throughout parts of coastal Maine, New Hampshire, and Massachusetts which lead to huge numbers of power outages in that region. Strong gusty wind also developed along the east facing slopes of the Green mountains, Berkshires and Taconic range with occasional gusts late Thursday night into early Friday morning ranging from 50-60 mph. (Rutland Vermont: Measured 58 mph easterly wind gust @ 2:55 am Friday, February 26)

And the storm did not stop after the initial twenty four hour onslaught. The strong Greenland jet stream block remained firmly in place acting to prevent any significant eastward motion of the system causing it to stall out over the Northeast through the weekend. Despite the system's deep feed of tropical moisture being cut-off and a pronounced weakening trend, it continued to produce bands of occasionally moderate to heavy snow Friday, Friday night, and through Saturday morning, with lighter patchy snow persisting through Sunday morning before finally ending early Sunday night. Communities in the Hudson valley and western New England that were hit with primarily rain during the first and most intense phase of the storm dealt with periods of heavy wet snow from Friday through the weekend. In general, snow accumulations from Friday through Sunday in valley locations ranged from 4"-6" with 6" to locally 12" in some higher elevation communities.

Margaretville, NY, Delaware County, 26" of new snow on Searles Road
7:00am Friday, February 26, 2010
Photograph by WeatherNet 6 spotters Hollice and Lucy Straut

Excessive snow in Margaretville, Delaware County, 7:00am February 26, 2010

Set Up
A strong upper level low pressure system plowing through the Ohio valley drove the development and initial motion of this storm into the Northeast. (In fact, the same prevailing pattern and upper level trough spun out the first disturbance which went on to produce the initial major snowfall on the 23rd and 24th.)

On Thursday morning, the 25th, the upper low was centered over southeast Ohio, cut-off from the main jet stream flow, with a favorable position and orientation to intensify an initially weak area of surface low pressure coming out of the Southeast, as that storm made its way up along the Atlantic coast. By Thursday evening, the upper low had moved to east central Virginia, with a strong southeast to northwest wind flow pattern on its eastern side. The now powerful surface storm was located southeast of the eastern tip of Long Island with the parent upper air system cutting in under it, forcing it to move northwest towards New York City. Rapid intensification occurred during this ballet around the upper low on its track to New York City, with the central pressure falling an average of 1mb to 2 mb per hour as it deepened to 973mb by 10pm. The combination of the storm's intensity, track, and especially its deep tropical connection, which had originated in the Pacific, but also streamed through the moisture rich environments of the Gulf of Mexico and Caribbean, and along and east of the Atlantic Gulf stream, produced the onslaught of heavy snow in the Catskills, with heavy rain in the Hudson valley and New England where the temperature profile was marginally warmer. The storm, with an observed eye-like feature at its peak intensity Thursday night, weakened considerably on Friday as it became vertically stacked under the parent upper air low. The entire system then stalled out over the region due to strong blocking at the steering level to its east and northeast. The parent upper low essentially stalled over or near Albany through Saturday with a southward drift of the center to near Scranton, PA on Sunday, then south of New England Sunday night. With colder air flowing into the entire system on Friday, the system went on to produce periods of snowfall, some moderate to heavy at times, Friday through Saturday morning, with lighter and more scattered snow through Sunday morning as the upper low and weak surface centers drifted away from the region.

Temperature Profile/Dramatic Rain-Snow Line
A unique thermal profile accompanied this storm which lead to the development of and quasi-stationary nature to the rain-snow line, which set up in the Hudson valley early Thursday morning, the 25th. Light scattered rain developed across the region just prior to midnight on the 24th becoming more widespread, steadier, and heavier, towards daybreak on the 25th. With a marginal temperature profile in place, with surface temperatures in the low to mid 30s in the Hudson valley, rain predominately fell, mixed at times with wet snow prior to daybreak during times when precipitation rates increased. A slight elevation shift up, however, and it was all snow from the onset and where the air was marginally colder in the Mohawk Valley, Adirondacks, and Catskills. A slightly colder temperature profile existed through the storm's duration in the mid Hudson valley as compared to the Capital Region, where tiny elevation differences meant the difference in a couple inches of snow and 15" of snow in portions of Dutchess and Ulster counties.

As the storm intensified late Thursday afternoon and Thursday evening, with a location south of eastern Long Island, its circulation was able to force relatively mild air into the region on a trajectory that would take it up over the Capital Region and into the eastern Mohawk valley and Adirondacks pushing the rain-snow line west into Montgomery, Fulton, Hamilton, northwest Saratoga and Warren counties. Conversely, what's called an ageostrophic wind flow, across the Catskills and mid Hudson valley allowed a much colder air mass to remain steady state or even push east into the mid Hudson valley after dark causing the rain-snow line to move east causing rain to change to snow in areas south of Albany through the night. Regional surface temperatures illustrated clearly illustrated the low level thermal profile At 10pm with a temperature at Glens Falls of 41° , 38° @ Albany, 32° @ Poughkeepsie, and around 20° @ Binghamton and Monticello. The 43° high temperature @ Albany on Friday the 26th occurred at 4:38am as warm air continued to stream into the Capital Region and points north as the storm center tracked to near NYC.

Dry Slot-End of Phase I
The end of the first, and most intense phase of snow and rain came between 1am and 4am Friday morning the 26th as a significant dry slot rapidly rotated all the way around the storm, coming into eastern New York and western New England from the east. Steady moderate to heavy rain and snow quickly broke up becoming lighter and more intermittent through the pre-dawn period. Rain from this initial surge of the storm never changed to snow in the Capital Region as air cold enough to support snow did not come in before the main precipitation shut down. Breaks of sunshine occurred in the region for a couple of hours early Friday morning in the dry slot before a dense overcast quickly redeveloped as colder unstable air slowly took over.

Phase II
With the dry slot pushing out of the region by the mid to late morning on the 26th plentiful low level moisture returned, coupled with increasing instability in the atmosphere due to cooling temperatures aloft, to allow bands of snow to quickly develop across the region through the late morning. Snow picked up in intensity through Friday afternoon, evening, and the overnight period into Saturday morning in some areas as this phase of the storm was generally marked by a more scattered and broken precipitation shield. Up to 6" of snow accumulated from Friday through Saturday morning in areas affected by the heavier banding. The process repeated through Saturday with periods of snow, moderate at times during the morning and afternoon, occasionally mixed with drizzle during the daylight hours as the storm sat and slowly spun itself out over the region through Sunday. By Sunday afternoon and evening, breaks of sunshine once again developed as the storm had pretty much ended across the region, concluding a week long siege in a winter that up until this period produced relatively few snow events.