(NOAA)

Twenty-five years ago, the Storm of the Century swallowed the Eastern Seaboard. Its snowfall isolated thousands of people in the Southeast and Mid-Atlantic. It paralyzed every major highway from Atlanta northward. It killed hundreds of people, did billions of dollars in damage and is still unlike any winter storm we have seen.

Here we revisit some of the most remarkable attributes of this amazing weather system.

It remains the costliest winter storm in U.S. history

The Storm of the Century has yet to be topped by any winter storm we’ve seen in more than two decades since. The effects stretched from Florida to Maine. It knocked out power to more than 10 million homes and businesses, many for multiple days. On top of the wind and snow, severe thunderstorms spawned tornadoes that caused significant damage across Florida.

Adjusted to 2017 U.S. dollars, the Storm of the Century cost $10 billion.

Record-low pressure and widespread damaging wind

The storm spawned in the warm waters of the Gulf of Mexico along the Florida panhandle. It strengthened rapidly as it tracked east and fell to 972 millibars over Georgia — a remarkably low pressure for a storm that was over land.

The system developed an enormous wind field, which maintained its large footprint as the coastal storm traveled north-northeast up the Eastern Seaboard. Peak wind gusts in the 60-70 mph range were common throughout the coastal Carolinas.

Over New England, central pressure bottomed out at 960 millibars. Low pressure records for March were set in 12 Eastern states. Several locations set all-time low-pressure records across the Southeast and Mid-Atlantic.


The size and intensity of the vortex was enormous, shown here on March 13 (left) and then March 14 (right). (NOAA)

A derecho and 11 tornadoes

An energetic phalanx of thunderstorms erupted during the early development phase of this cyclone, sweeping across Florida and Cuba. The severe squall line developed in the storm’s warm sector (southeastern quadrant), and is now recognized as a derecho (a long-lived, long track, convectively induced windstorm).

The derecho rapidly swept through the western Caribbean after midnight March 13. Straight-line winds reached 100 mph, and 11 tornadoes touched down.


Figure 2 Infrared satellite image of the 1993 Superstorm on March 13. Yellow regions delineate exceptionally cold cloud tops, part of a massive squall line sweeping through the storm’s warm sector. (NOAA)

The widespread, severe gusts attest to the exceptional vigor of this wintertime squall line, and thus the larger cyclone in which the local storms were embedded.


The “ancient art” of hand-drawn meteorological analysis depicting the Superstorm’s derecho progressing across Florida (wind gusts in mph shown) during the early morning of March 13. Numbers over Cuba indicate peak gusts (mph) from the same derecho. (NOAA)

Heavy snow over a record-long swath

Along the storm’s northern and western sectors, the prodigious Gulf moisture condensed and froze. Significant snow fell from the Gulf of Mexico to beyond Maine.

More than 20 inches of snow fell along this swath with isolated regions of 30 or more inches. The blockbuster snow avoided the major cities of the Northeast, but 14 inches fell at Dulles, 6.5 inches at Washington Reagan (where sleet mixed in) and Baltimore picked up an impressive 12 inches.


Snowfall totals from the Storm of the Century. (NOAA)

The total volume of snow was estimated to be 13 cubic miles with a weight of up to 27 billion tons. Melted, the snow would have flooded 44 million acres of land one-foot deep.

The Northeast Storm Impact Scale (NESIS), designed to assess the combined effects of snow volume and population density, propels this storm into its top tier of ratings — a rare Category 5. This category is shared with only one other storm of record, the Blizzard of 1996.

An amazingly accurate forecast

This storm was a milestone in medium-range forecasting for the U.S. forecasts produced by several numerical weather prediction models were remarkably congruent and on-target five days in advance. The accuracy was such that forecasters were able to issue blizzard warnings for some regions two days before impact. NWS offices used special wording concerning this storm, days in advance, including “a storm of historical proportions.” States of emergency were declared before the first flakes ever flew.

The figure below shows just how tight model guidance of the day was clustered. The MRF is the American model (Medium-Range Forecast model); the ECMWF is an early version of the European Center for Medium-Range Forecasting model. The observed track (dotted line) runs right up the center of the exceptionally narrow guidance envelope. This singular event, perhaps more than any other, inspired our modern confidence in medium-range weather prediction.


Remarkably consistent five-day prediction of the Superstorm’s center track, as made by the U.S. MRF and European ECMWF models … as compared against the observed track. (Dickinson et al., 1997, Monthly Weather Review)