More than 55 firefighters from the Montgomery County Fire and Rescue Service battled a fully involved house fire on the 18700 block of Calypso Place in Gaithersburg on Tuesday after a blaze at the rear of a split-level home triggered a second alarm within minutes.

Crews first responded around 5:35 p.m., according to radio transmissions monitored by Bethesda Magazine. Firefighters reported heavy fire burning through the ceiling and roof by roughly 5:40 p.m., when the second alarm was called.

All occupants were accounted for, crews confirmed over the radio.

A "heavy column of smoke" was visible from MCFRS Fire Station 8 on Russell Avenue, roughly a mile from the scene. The station is operated by the Gaithersburg-Washington Grove Volunteer Fire Department.

MCFRS posted on social media around 6 p.m., according to Bethesda Magazine's report, confirming that more than 55 firefighters were working the scene of a fully involved single-family house fire.

The cause of the fire has not been announced. MCFRS has not issued a formal press release.

How to prepare

The Cabin John Park Volunteer Fire Department, which serves Potomac, West Bethesda, and Cabin John, advises residents to maintain two exits from every room and designate a family meeting place outside the home. MCFRS offers free Home Fire Safety Visits for Montgomery County residents; call 311 or visit montgomerycountymd.gov to schedule.