The Alabama Climate Report

Brought to you by the Office of the Alabama
Climatologist

Volume 9, Number 1, April 2018

Let’s talk about record-breaking weather.

By now you might have heard that a large hailstone that fell in Cullman County on March 19 has officially been declared to be the largest hailstone to fall on Alabama.

An ad hoc committee that included the Alabama state climatologist and officials from both the National Weather Service and the National Centers for Environmental Information reviewed data about the hailstone and unanimously agreed it will set the initial state hailstone record for Alabama in four parameters: diameter, weight, volume and circumference.

The record-setting hailstone in Walter (about 10 miles southeast of Cullman) had a maximum diameter of 5.38 inches along its longest axis. It weighed 9.8 ounces (almost 5/8 of a pound) and had a total volume of 19.8 cubic inches. According to the Insurance Institute for Business and Home Safety (IIBHS) in Tampa, a baseball has a volume of about 13.4 cubic inches, while a 12-ounce soft drink can has a volume of 25 cubic inches.

This is the first official record for a hailstone in Alabama.

“Was this the largest hailstone that fell that day or from this event?” asked Victor Murphy, climate and co-op services program manager at the National Weather Service’s southern regional headquarters in Fort Worth, TX. “We don’t know, but it is the largest one that was kept and recorded.”

Which brings us to one of the more interesting things about hailstone records: Anyone can play. Anyone can pick up a hailstone and put it in the freezer. It’s a very democratic process. With few exceptions, official records for temperature highs and lows and for rainfall, snowfall and snow depth can only be accepted into the official records if they come from an officially sanctioned, sanctified and standardized weather station.

The exception? Data provided by volunteer members of the Community Collaborative Rain, Hail and Snow Network (CoCoRAHS) is now being included in official reports of rainfall, and CoCoRAHS reports of record-breaking events can also go through the validation and certification process as state and national records.

What are Alabama’s other weather records?

Max Temp:      112° F          Sept. 6, 1925            Centreville, Ala.
Min Temp:     -27° F            Jan. 30, 1966            New Market, Ala.
24-hr. rainfall   32.52”         July 19-20, 1997      Dauphin Island, AL
24-hr. snow     20”               March 13, 1993        Walnut Grove, AL
Snow Depth    22”               Jan. 24, 1940            Reform, AL

Knowing a hailstone that fell March 19 in Walter was the largest to fall in Alabama — and one of the three largest ever documented east of the Mississippi River — is only half of the story.

The other half is learning how the record-setting hailstone compares to others that fell on Alabama in the past. To document the record and learn how it compares to hailstones from the past, my office is establishing a state hailstone record.

We are investigating earlier reports of large hailstones, but these reports are for information only and won’t be part of the official record. With a record-setting hailstone in hand, researchers would like more information about large hailstones that fell in the past and those that fall in the future.

For past storms, send documentation by email that must include a photo of the hailstone beside a ruler or tape measure for evidence of the size. Please include contact information, the date of the event, the exact location and the time of day the hailstone fell.

We have several historic accounts of four-and-a-half inch hailstones falling in Alabama. But we don’t need stories. We need evidence. Then we can compile a list of unofficial reports as background.

For hailstones that fall in the future, please immediately put the hail in a zip lock bag and put it in the freezer. Unless it is bagged, hail sublimates (evaporates) directly from ice to water vapor even if it is stored below freezing.

Information about past and future hailstones can be emailed to: weather_record@nsstc.uah.edu

The largest hailstone ever recorded in the U.S. fell on July 23, 2010, in Vivian, SD. It was 8 inches in diameter, 18.62 inches in circumference, and weighed 1.93 pounds.

April was a record-setting weather month for parts of Alabama, but that is the case almost every month. Daily records are broken on a fairly routine basis because the sheer number of types of events we track for records (heavy rainfall, drought, high temperature, low temperature, etc.) makes “record-breaking” a target-rich environment. For example, 58 stations in Alabama reported daily rainfall records in April, so 58 times 30 days means there were 1,740 opportunities for a daily rainfall record to be set.

At least five stations in Alabama had their all-time wettest April days on April 14 and 15. Thomasville got 8.21” on April 14, breaking the 5.47” record set in April 1979. On April 15, Chatom got 7.1”, breaking the 6.75” record set in 1954; Jackson got 6.06”, breaking a record set in 1974; Addison got 4.34”, breaking a record set in 2014; and Millers Ferry Lock and Dam got 4.11”, breaking a record set in 2003.

- John Christy
The Alabama State Climatologist