Great Appalachian Storm of November 1950
|Category 5 "Extreme" (RSI: 32.31)|
Surface Analysis showing cyclone near time of maximum intensity on November 25, 1950
|Formed||November 24, 1950|
|Dissipated||November 30, 1950|
|Lowest pressure||978 mbar (28.88 inHg)|
|Maximum snowfall or ice accretion||57 inches (1,400 mm)|
|Damage||$66.7 million (1950 dollars)|
|Areas affected||Eastern Third of the United States and Southeast Canada|
The Great Appalachian Storm of November 1950 was a large extratropical cyclone which moved through the Eastern United States, causing significant winds, heavy rains east of the Appalachians, and blizzard conditions along the western slopes of the mountain chain. Hurricane-force winds, peaking at 110 miles per hour (180 km/h) in Concord, New Hampshire and 160 miles per hour (260 km/h) in the New England highlands, disrupted power to 1,000,000 customers during the event. In all, the storm impacted 22 states, killing 353, injuring over 160, and creating US$66.7 million in damage (1950 dollars). At the time, U.S. insurance companies paid more money out to their policy holders for damage resulting from this cyclone than for any other previous storm or hurricane. The cyclone is also the highest-ranking winter storm on the Regional Snowfall Index with a maximum value of 32.31; and one of only sixteen storms to rank as a Category 5 on the scale. 
- 1 Synoptic history
- 2 United States effects
- 3 Effects in Canada
- 4 Lasting impact
- 5 Other similar storms
- 6 See also
- 7 References
- 8 External links
The preceding atmospheric state was one of La Niña conditions, the cold phase of ENSO, which favors a storm track from the Ohio and Tennessee Valleys into the Appalachians. The cyclone initially formed in southeast North Carolina near a cold front on the morning of November 24 as the main cyclone over the Great Lakes weakened. Rapid development ensued as the surface center began to migrate back into a closed 500 hPa (14.75 inHg)-level (around 6,000 m/20,000 ft above sea level) cyclone, and the cyclone bombed while moving north through Washington D.C. the next morning. The former occluded front to its northwest became a warm front which moved back to the west around the strengthening, and now dominant, southern low pressure center. By the evening of November 25, the cyclone retrograded, or moved northwestward, into Ohio due to a blocking ridge up across eastern Canada. It was at this time that the pressure gradient was its most intense across southern New England and eastern New York. A wide area of +4 standard deviation 850mb winds occurred. The cyclone moved west over Lake Erie to the north of the upper cyclone before looping over Ohio as the low-level and mid-level cyclone centers coupled. Significant convection within its comma head led to the development of a warm seclusion, or a pocket of low level warm air, near its center which aided in further development due to the increased lapse rates a warmer low level environment affords under a cold low. After the system became stacked with height, the storm slowly spun down as it drifted north and northeast into eastern Canada over the succeeding few days.
United States effects
This extratropical cyclone rapidly deepened as it moved up the eastern side of the Appalachians during November 24 and November 25 and continued into November 27. Coastal flooding was seen along the U.S. coastline from New Jersey northward.
In Alabama, all-time record lows for November were set at Birmingham 5 °F (−15 °C), Mobile 22 °F (−6 °C), and Montgomery 13 °F (−11 °C). Across Florida, all-time record lows for November were set at Apalachicola (24˚F), Pensacola (22˚F), and Jacksonville (23˚F). Within Georgia, all-time record lows for November were set at Atlanta (-3˚F), Columbus (10˚F), Augusta (11˚F), and Savannah (15˚F).
An all-time record low for November was set at Louisville (-1˚F).
Sustained winds of 50-60 mph (80–100 km/h) with gusts to 83 miles per hour (134 km/h) were recorded at Albany, New York. A wind gust of 94 miles per hour (151 km/h) was recorded in New York City. Extensive damage was caused by the wind across New York, including massive tree fall and power outages. Coastal flooding breached dikes at LaGuardia Airport, flooding the runways. Flooding extended to New York City's Office of Emergency Management on the Lower East Side, in Manhattan.
Extensive wind damage with tidal flooding along the coast. On the coast structures and railroad tracks washed away. Plows were needed to remove sand from coastal roads. Roofs torn off on the coast and at the University of Connecticut. The tide at New London was 7.58ft MLLW third highest in the last 100 years. Hartford had sustained winds of 70MPH the highest ever on record, 100 MPH gusts also the highest on record were recorded on 3 separate occasions. The 62 MPH sustained wind recorded at Bridgeport is the 4th highest on record. Other gusts 88MPH at Bridgeport and 77MPH at New Haven.
On the storm's west side, nearly a foot of snow fell on Dayton, Ohio, which combined with the wind and cold temperatures, became their worst blizzard on record. Nearly the entire state was blanketed with 10 inches (25 cm) of snow, with 20-30 inches (50–75 cm) being measured in eastern sections of Ohio. The highest report was 44 inches (110 cm) from Steubenville. Snow drifts were up to 25 feet (7.6 m) deep. Winds exceeded 40 miles per hour (64 km/h) with gusts as high as 60 miles per hour (97 km/h). Bulldozers were used to clear roads. Despite the high winds and snow, the annual football game between the University of Michigan and Ohio State University went on as scheduled in Columbus and was nicknamed the Snow Bowl. When the snow melted during the first four days of December, river flooding occurred in Cincinnati.
During the height of the storm, record to near-record flooding occurred along the eastern side of the Appalachians across eastern and central sections of the state. The Schuylkill at Fairmont Dam reached its highest stage since 1902. In Pittsburgh, 30.5 inches (77 cm) of snow accumulated from this cyclone. Tanks were used to clear the resultant snow. When a warm spell visited the region during the first four days of December, river flooding struck Pittsburgh.
Parkersburg recorded 34.4 inches (87.3 cm) of snowfall during the passage of this low, which exceeded its snowiest November on record by over 5 inches (13 cm). Pickens reported the highest amount from anywhere within the cyclone, with 57 inches (140 cm) measured. November 1950 became West Virginia's snowiest month on record. This remarkably heavy snow led to 160 deaths.
Effects in Canada
This cyclone was used as a test case for some of the first attempts at numerical modeling of the atmosphere, and is still used as a case study to run recent versions of forecast models. These studies helped create what is now known as the National Centers for Environmental Prediction.
Other similar storms
Storms during the time frames November 8–10, 1913, October 22–25, 1923, and November 19–22, 1952 were considered analogous to this cyclone. Despite their similarities, there are some differences. For example, the 1913 event was much more destructive to Great Lakes shipping, while the 1950 storm caused greater snowfall amounts.
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