Ice Storm — Montgomery, Maryland

1999-01-14 to 1999-01-15 · Montgomery, Maryland

Wider weather episode

A strong arctic cold front moved slowly southeast across the Mid-Atlantic region from late on the 13th to midday on the 15th. This front brought a thick layer of sub freezing air to the lowest levels of the atmosphere, but just off the surface warmer air moved in. A low pressure system developed on the 13th over the Tennessee Valley. The low moved into the Mid Atlantic region over the next few days, spreading precipitation region wide from early on the 13th through midday on the 15th. The precipitation started as snow but melted into rain as it fell through the warm layer of air. Unfortunately west of the cold front the ground was below freezing during the period so the rain froze on every surface it came in contact with. This created ice accumulations of one quarter to one half inch north and west of a line from Montgomery County to Harford County through early afternoon on the 14th. By 9 AM on the 15th, ice accumulations from one quarter to nearly one inch occurred across all of Western and Central Maryland, except Charles, Calvert, and St. Mary's county where a trace to one quarter inch accumulated. The ice this storm left behind had a large impact on the region. Hundreds of car accidents, slip and fall injuries, downed trees, and power outages were reported. On the morning of the 14th, 30 Montgomery County school buses slipped off the road. Interstate 68 in Allegany County was closed from midnight to 3 AM on the 15th because of several accidents. A 21 year old man was killed in a car crash on Interstate 70 in Western Maryland around 5 PM on the 15th, west of Conocheague Creek, and a tractor trailer jackknifed at 2:30 AM on the 16th near Exit 9. The city of Annapolis in Anne Arundel County reported 37 car accidents with two serious injuries. The icy conditions also led to over 500 pedestrian slip and fall injuries. One hospital in the Washington suburbs treated over 250 patients alone on the 15th with storm related injures. Winds gusted over 40 MPH after the precipitation ended and trees weighed down by the heavy ice accumulations fell on homes, across roads, and onto power lines across the area. 2000 power lines were reported down in PEPCO's Maryland power service area leading to a loss of power for 230,000 of the utility companies 680,000 customers. This was the worst ice storm in PEPCO's service history. The Governor declared a state of emergency in Howard, Prince Georges, Carroll, Baltimore, Harford, and Montgomery Counties. Montgomery County was the hardest hit location. Nearly 187,000 customers in the county were without power, and some locations did not have power restored until the 19th. Over 200 people were housed in emergency shelters. 1,223 live power lines were downed by the storm. 11 of the 41 power substations were knocked out across the county, in addition to 430 of 700 traffic lights. Also, 34,000 customers in Prince Georges County, 119,000 in Baltimore County, 39,000 in Howard County, 7,600 in Anne Arundel County, and 5,000 customers across Western Maryland were without power after the storm. Power outages also caused a disruption in the public transportation system in the suburbs of Washington D.C., leading to a commuter nightmare. The Red Line of the Metro subway system had to be shut down from the Van Ness to Shady Grove Station in Montgomery County at 3:30 PM on the 15th after rail de-icing equipment failed and a tree fell across the tracks. The MARC train system had to cancel departures from Washington D.C. westward between 5 and 6 PM due to ice and related power outages.

Source: NOAA Storm Events Database, event_id 5680091. Narrative written by the NWS forecast office that issued the report.