One person died and at least 30 people suffered injuries when a deadly late-night tornado struck north of Birmingham, Ala., on Monday night. The densely populated suburb of Fultondale was ravaged by the twister, which tossed about cars and destroyed homes and businesses.

The strong tornado touched down in an environment that otherwise appeared marginal for the threat of severe weather, with significant tornadoes unlikely. It’s reminiscent of a similar deadly tornado that struck Nashville in March in the middle of the night, forming in an environment that presented no obvious strong tornado signals.

Classes have been canceled at Fultondale High School, which was directly impacted by the tornado. The twister touched down around 10:43 p.m., roughly nine minutes after a tornado warning was issued by the National Weather Service in Birmingham. Several people have credited the timely warning with saving lives.

The tornado first touched down near Interstate 65 at Exit 267 in Fultondale, damaging a shopping complex off Lowery Parkway. It then caused severe damage to hotels along the intersection of Walker Chapel Road and Highway 31, a busy commercial zone. Republic Avenue and Carson Road near Yarbrough were also impacted, as were the adjacent subdivisions; the twister also appears to have passed near American Legion Post 255.

First responders urged residents to avoid the area following the storm while rescue and recovery operations were underway.

Daylight revealed extensive damage is likely to commensurate with an EF3 tornado, with winds probably topping 140 mph. That matches with radar signatures that indicated a strong rotational couplet, as well as debris tossed to nearly 18,000 feet. That’s a surefire sign of an intense tornado.

A cold front crossed through the South late Monday, a change of wind speed and direction with height accompanying the frontal passage. That brewed an environment with strong wind shear, which set storms rotating.

Storm tops grew taller than 40,000 feet, heights more than sufficient to feel the atmosphere’s changing winds. Meanwhile, wind shear strengthened with sunset as the low-level jet stream, or a river of southerly winds about 10,000 feet above the ground, intensified.

However, the unusual setup featured wind shear that was most impressive close to the ground and actually weakened higher up.

“There was something going on with the winds,” said Kevin Laws, a meteorologist at the Birmingham Weather Service Office. “I didn’t think the winds were that good. Winds were coming out of the southwest, and we don’t really get tornadoes with winds out of the southwest.”

It’s likely that a tiny, local temperature or wind boundary played a role in enhancing easterly winds near Fultondale, helping twist up the storm.

“We keyed in on that,” Laws said. “I’m sure that was a final trigger point.”

Those elements overlapped with the front, or the storms’ triggering mechanism, to yield a narrow spot of tornado ingredients just north of Birmingham. The tornado developed quickly and fell apart quickly, but was on the ground long enough to cause serious damage.

A man who was sheltering in his basement with family members died, Fultondale Police Chief D.P. Smith confirmed to, adding that several family members were critically injured.

The overarching setup was one that meteorologists dread because of the difficulty in forecasting whether storms will become severe — so-called “high shear low CAPE environments.” CAPE, which stands for convective available potential energy, refers to an amount of instability or atmospheric fuel present. When CAPE is low, it diminishes but does not eliminate the chance for severe storms if a lot of wind shear is present.

Even as storms grew Monday night, the Weather Service Storm Prediction Center wrote, “it’s not entirely clear why this activity has increased.”

Under the atmospheric conditions that were present Monday night, severe storms are usually scarce but, once in a great while, disaster strikes.

That was the case last year on the night of March 2, when a pair of long-track, violent tornadoes struck Nashville and suburbs to its east. More than two dozen people perished, including five in the first tornado, which struck without warning. Residents had been told there was a very low risk of tornadoes before the latter tornado, an EF4, touched down.

However, Monday night’s tornado in Alabama proved the opposite. Not only was there a tornado watch up hours in advance to highlight the potential of twisters, but Weather Service meteorologists provided nine minutes of lead time with a tornado warning.

Despite radar signatures for a tornado present being subtle at the time, the warning proved prescient — and the resulting wireless emergency alert awoke many residents who had gone to bed.

It was a case where forecasters did everything right and are likely to have minimized loss of life.

“If you’re in the mind-set and ready for it, if you believe the environment and what’s going on, you’ll be ahead of it,” Laws said. “It goes into the environment mind-set where you’re on the ball looking for these things.”

Monday night’s tornado in Fultondale was the only report of severe weather in all of Alabama.

Alabama averages about three tornadoes during the month of January each year, meaning January twisters aren’t entirely rare. They are often overlooked since they occur in more marginal setups without the broader severe weather that accompanies larger springtime tornado outbreaks.

Alabama is actually much more likely to be impacted by a tornado during the months of January or February than any time between June and October, indicating that periodic wintertime severe weather setups can be expected. Wind dynamics are often supportive of tornadoes, but cool weather during the wintertime is usually a limiting factor.