Two firefighters were killed today while battling a row house fire in Boston's Back Bay neighborhood. Thirteen more suffered non-life-threatening injuries.

It isn't yet known how the fire started, but today's 40-plus mph winds caused it to spread rapidly. Deputy chief Joseph Finn told WCVB: "In 30 years, I have never seen a fire travel that fast, escalate that quickly and create such havoc in such a short period of time." 

Lt. Ed Walsh, 43, and Mike Kennedy, 33, were in the basement of the house when they became trapped and signaled for help. A backdraft explosion injured several firefighters when they entered the house to rescue Walsh and Kennedy. Eighteen people were taken to area hospitals, at least 13 of whom were firefighters.

All the residents of the four-unit building are accounted for. The fire is under control, though parts are still burning.

Kennedy and Walsh are the first Boston firefighters to die in the line of duty since 2009.

"We lost two heroes here today," Boston mayor Martin Walsh said at a press conference. "Today is just a sad day in the city of Boston."