Major Storm, Regional Elevation Ice Storm-Excessive Rain-Flooding
Tuesday-Wednesday March 4-5

Flooding
Had it been snow, this storm could have been epic. As it was the basin wide average of 1.75" to 3" of rain that fell in approximately eighteen hours put this storm pretty close to the top of the scale when it comes to precipitation generation. Widespread but generally minor flooding resulted from the deluge with small streams and creeks spilling out of their banks. Urban poor drainage flooding closed roads, inundated some basements, and generally caused a great deal of inconvenience for many as storm drains clogged with ice and snow blocked the enormous runoff from harmlessly draining away.

WeatherNet 6 spotter James Van Voorhis Jr. supplied this photograph of the Catskill Creek in Preston Hollow, Albany County as it appeared on March 5 during the late afternoon. The scene is representative of what most area streams and creeks looked like in the wake of the excessive runoff from the storm.

The Catskill Creek in Preston Hollow, NY running high after 2 

Ice Storm
Ice storm conditions brought branches and power lines down in the hard hit higher elevations of Schoharie and Otsego counties, as well as throughout the Adirondacks, northern Saratoga and Washington counties. Ice accumulations ranged from 1/2" to as much as 1" in a few locations in the ice storm zone. Icing developed in the Mohawk valley and Capital Region as well but generally did not last as long with a quicker change back to rain resulting in lighter ice accretions. Aside from a period of slick travel on untreated roads during the pre-dawn hours on the 5th, the icing in the Capital Region did not lead to any serious problems.

The Set-Up
March 4, Morning
A cold frontal passage during the morning replaced a mild air mass with a much chiller one as the wind shifted into the north causing temperatures to fall into the 30s. With the quick arrival of the colder air over the region the stage was set initially for light mixed wintry precipitation as moisture running well in advance of the main storm, located in the Tennessee valley, overran the colder air filtering into New York. Light rain broke out during the early to mid morning, quickly mixed with and changed to sleet, and briefly snow in some areas as the air became colder. The zone of precipitation, however, was narrow, running along and behind the cold front which stalled out across central Pennsylvania by the mid afternoon. A region of low and mid level dry air worked into the Adirondacks and Catskills just behind the narrow zone of precipitation on the north side of the front. This dry air region did two things, 1) caused precipitation to dry up across the Adirondacks into the afternoon and evening, and 2), set the stage for a period of strong cooling due to evaporation when the main bulk of precipitation hit the region during the mid to late afternoon and overnight period. The evaporative cooling process proved to be instrumental in creating ideal conditions for the elevation ice storm that ensued through the night.

March 4, Late Afternoon-Midnight:
A strong and intensifying storm moved up from Kentucky to southern Pennsylvania through midnight accompanied by a fire hose of moisture streaming north from the Gulf of Mexico. The storm's circulation drove mid level warm air into the Northeast through the evening causing any snow and sleet to change to rain which froze on surfaces in the parts of the region where temperatures dropped to below 32°. As rainfall increased in coverage and intensity during the afternoon and the evening, evaporative cooling increased over the higher elevations of the Catskills and Adirondacks causing temperatures to drop into the upper 20s resulting in serious ice storm conditions developing with the hardest hit areas including Schoharie and Otsego counties, the Adirondacks to northern Saratoga and Washington counties. The northerly low level cold air drainage flow also allowed temperatures to drop to 32° into the Capital Region prior to midnight and remain there through the pre-dawn hours of the 5th allowing icing to occur as well. The icing, however, in the lower elevations was of a shorter duration and less robust with temperatures frequently bouncing back and forth between 32° and 33° as the freezing process released enough heat to offset the weakening flow of colder air into the region. (In general, ice accretion is much more efficient with air temperatures below 30°, which occurred in the higher elevations accounting for the heavier ice build-ups)

Figure #1 is a graphical representation, derived from WeatherNet 6 and National Weather Service spotter reports, of the areas affected by icing during the March 4-5, 2008 Storm

Figure #1

Icing Distribution and amounts from the March 4-5, 2008 Storm 

Reported Ice Accumulations for the March 4-5, 2008 Storm

Town

County
Ice Accumulation Report

Savoy, MA (2400")

Berkshire
0.38"
Rensselaerville Albany
0.67"
Altamont Albany
1/2"

Knox

Albany
1/2"
Indian Lake Hamilton
1/2"
Arietta Hamilton
1/4"
Wells Hamilton
1/4"
Glen Mongtomery
1/4"
Brunswick Rensselaer
1/10"
Saratoga Springs Saratoga
0.20"
Clifton Park Saratoga
1/10" to 1/4"
Delanson Schenectady
1/2"
Niskayuna Schenectady
0.20"
Seward Schoharie
3/4"
North River Warren
1/2"
Glens Falls Warren
1/4"
Dresden Washington
1.00"
Landgrove, VT Bennington
1/4"
Wilmington, VT Windham
1.00"

Click Here for Ice Storm Pictures

Wednesday March 5:
Heavy icing in the western Catskills and throughout much of the north country changed to rain towards daybreak as the low center moved into central New York allowing a warm frontal passage to occur. The subsequent wind shift into the south allowed a surge in temperatures through the morning into the low 50s across the mid Hudson valley and into the mid 40s into the Capital Region with upper 30s in the ice storm zones ensuring the last phase of the storm would be rain.

Powerful jet stream dynamics accompanied the passage of the surface storm and cold front during the morning resulting in a period of torrential convective rain between 7am and noon across eastern New York and western New England. The stronger convective elements in the Hudson valley produced a few lightning strikes and brief wind bursts in excess of 40 mph. The storm, moving rapidly, pulled out of the region during the early to mid afternoon with only scattered mixed rain and snow showers in its wake and gusty WNW winds which ranged from 30-40 mph at times into the nighttime hours.

This table lists the WeatherNet 6 and National Weather Service observed storm total rainfall reports for the March 4-5, 2008 Storm

Town

County Rainfall Report Town County Rainfall Report

Savoy, MA (2400")

Berkshire 1.13" Lanesborough, MA Berkshire 1.60"
Lenox Dale, MA Berkshire 1.21" Pittsfield, MA Berkshire 1.44"
North Adams, MA Berkshire 1.12"      

Sharon, CT

Litchfield 1.42"      
Latham Albany 2.50" Medusa Albany 1.53"
Albany (NWS) Albany 2.53" Colonie Albany 2.57"
Cohoes Albany 2.25" Preston Hollow Albany 2.20"
Voorheesville Albany 2.79" South Berne Albany 2.70"
Kinderhook Columbia 3.00" Livingston Columbia 2.22"-2.48"
Ghent Columbia 1.90" North Chatham Columbia 1.64"
Stuyvesant Falls Columbia 2.05"-2.70" Ancramdale Columbia 1.30"
Taghkanic Columbia 1.54" Chatham Center Columbia 1.80"
Red Hook Dutchess 3.25" Poughkeepsie Dutchess 1.50"
Millbrook Dutchess 1.48" Clinton Corners Dutchess 1.30"
Margaretville Delaware 2.20"      
Broadalbin Fulton 1.36"      
Catskill Greene 2.63"-3.03" East Jewett Greene 3.08"
Piseco Hamilton 1.42" Indian Lake Hamilton 1.38"
Wells Hamilton 2.50"      
Fonda Montgomery 1.80" St. Johnsville Montgomery 1.75"
Amsterdam Mongtomery 1.80" Fonda Montgomery 1.94"
Glen Montgomery 2.25"      
Stephentown Rensselaer 1.60" Center Brunswick Rensselaer 1.82"
Brunswick Rensselaer 2.46" Eagle Mills Rensselaer 2.30"
Buskirk Rensselaer 1.60"      
Charlton Saratoga 1.80" Gansevoort Saratoga 2.50"
Stillwater Saratoga 2.00" Malta Saratoga 1.98"
Clifton Park Saratoga 2.51"      
Scotia Schenectady 2.05" Delanson Schenectady 1.83"
Niskayuna Schenectady 1.86"      
Jefferson Schoharie 3.00" Howes Cave Schoharie 2.74"
Charlotteville Schoharie 2.50"      
Whiteport Ulster 2.81" Phoenicia Ulster 3.64"
Kingston Ulster 2.94" Esopus Ulster 2.10"
Saugerties Ulster 2.92"-3.18" West Shokan Ulster 2.74"
Fort Edward Washington 2.15" Granville Washington 2.25"
Cossayuna Washington 2.13"      
Glens Falls Warren 2.14"      
Bennington, VT Bennington 1.35"