Build an Ark: 3 Inches of Rain Fell in 25 Minutes Last Night

There's heavy rain, and then there's heavy rain. The storms that hit southern Alabama last night were leftovers from the tornado outbreak earlier in the day, but they packed one heck of a punch. Mobile, Alabama saw 3 inches of rain in just 25 minutes.

The University of South Alabama in Mobile (from which I graduate next week — go Jags) has an extensive network of weather stations set up across the northern Gulf Coast, and one of these stations is on USA's campus itself. The rain gauge at the station measured incredible amounts of rain as the wall of rain and wind hit the city of 200,000 just before 2:00 this morning.

Build an Ark: 3 Inches of Rain Fell in 25 Minutes Last Night

The rain started at 1:55 AM, and the it hit so fast and so hard that its line on the rainfall graph (pictured above) is almost completely vertical. Here are select rainfall totals measured in minutes after 1:55 AM:

1 minute: 0.01"

5 minutes: 0.46"

8 minutes: 0.97"

10 minutes: 1.39"

15 minutes: 2.26"

20 minutes: 2.81"

23 minutes: 3.00"

25 minutes: 3.11"

66 minutes: 4.00"

The storm total for the event was about 4.34 inches*, not including the extra two plus inches that have fallen since noon today. It was an incredible rainfall and one of the hardest to hit Mobile in recent memory. The only other rainfall event in the last five years that comes close would be May 2, 2012, which had similar amounts of rain but spread out over the course of several hours.

While these rainfall rates are impressive, they can't hold a candle to the rainfall rate records set in the United States — the most rain to fall in 1 minute in the U.S. was 1.23 inches in Unionville, Maryland back in the 1950s.

Last night's heavy rains weren't limited to Mobile. Flash flooding occurred across the Deep South as a result of the deluge as areas across Alabama and Mississippi have seen between 4 and 6 inches of rain over the past two days. More rain is expected through tonight until drier air moves into the region tomorrow.

UPDATE: Drier air didn't move in and we wound up seeing 11.84" of rain in 29 hours, produced by the same storms that caused catastrophic flooding in Pensacola, Florida.

*USA Mesonet uses two different rain gauges, a standard rain gauge (TX) and a "tipping bucket" gauge (TB3). Tipping bucket gauges are inaccurate during extreme rainfall events like the one seen last night, so I didn't use it here.

[Images via USA Mesonet and Gibson Ridge]