EF1 tornado in Howard County, Maryland

A supercell thunderstorm moved through northern Montgomery and northwestern Howard Counties in Maryland during the evening hours of Wednesday March 11, 2026. The bow echo and associated downbursts/thunderstorm wind gusts caused sporadic tree damage from 60-80mph gusts, and created a brief EF-1 tornado, with focused tornadic damage near Cooksville in northwestern Howard County. On March 12, staff from the National Weather Service Baltimore/Washington Weather Forecast Office conducted a ground survey of the storm damage. The survey started near Damascus and extended through northwestern Howard County. There were numerous instances of trees uprooted or snapped, as well as damage resulting from downed trees. Tree fall was generally in the direction of the storm's easterly movement. Ground evidence suggested the thunderstorm produced scattered wind damage along its path from 60 to 80 mph wind gusts. However, as the storm continued east-northeastward, crossing the interchange of I-70 and MD-97, damage was observed 300 yards southwest of Old Frederick Road, crossing Old Frederick Road between Forsythe Road and Underwood Road. Here, along a treeline to the southwest of Old Frederick Road, approximately 50 trees were uprooted or snapped across an approximately 100 yard wide swath. Several of the uprooted trees fell at right angles to each other. Additional trees were snapped or uprooted near residences to the northeast of the road. The tornado appeared to have briefly lifted before touching down a final time at a residence on Underwood Road, where several trees were uprooted and snapped in multiple directions. This damage is indicative of a low-end EF-1 tornado. Additional to the ground survey, Doppler radar information from KLWX (Sterling VA radar) and TBWI (FAA BWI radar) was analyzed. Radar showed a powerful storm with broad rotation aloft along its path. From radar analysis coupled with ground observations, it was determined that an EF-1 tornado formed at 7:06pm and lifted at 7:08pm, with estimated winds up to 90 mph, a path length of 0.4 miles, and a maximum width of 100 yards. Special thanks to Howard County Office of Emergency Management for their assistance. Additionally, thanks to the trained spotters, media, and public that sent in reports of damage.

A powerful cold front spawned a narrow corridor of bowing line segments and line-embedded supercells, resulting in damaging straight-line wind gusts and tornadic damage.