Volume 7, Number 1 - October 2016
Alabama Octobers can be dry. In our survey of 25 sites around the state, through October 2015 eight of those sites reported 0.00" as their lowest October rainfall on record.
Of those 25 sites, nine reported 0.00" of rain in October 2016, and eight others saw less than 0.1" for the entire month. Our 25-site statewide average rainfall for October 2016 was a trifling 0.16"; normal rainfall is about 3.20" for the month. The official driest October in Alabama's climate record was in 1963, when the statewide average rainfall was 0.03".
But as dry as October was — and it will be among the driest Octobers on record — it is the combination of intense drought in both September and October that will set 2016 in the record books.
While dry Septembers and dry Octobers aren't rare in Alabama (from 1904 through 2016, Birmingham got less than one inch of October rain 20 times; in Montgomery, it happened 30 times), two autumn months of back-to-back intense drought are few and far between.
Birmingham recorded 0.00" of rain in October and 0.68" in September. The only other time on record when Birmingham got less than one inch of rain for both September and October in the same year was in 1904 (October 0.24" and September 0.44").
Huntsville's rain records go back to 1907. It had never seen a September and October where both months got less than one inch of rain, until 2016 (September 0.47" and October 0.77").
Drought and heat frequently go hand in glove, and that was the case in October. While we wait for the official standing of October's mean temperature, we wanted to look at just the high temperatures. While the heat set 110 daily high temperature records in October, what was unique about this heat wave was its persistence.
The high-pressure ridge that pushed both rain and cool air north of Alabama throughout September and October hasn't yielded a bit. It was generally as warm at the end of October as at the beginning. The collective effect was a month that just didn't cool.
If we consider only the daily high temperatures in October, the average for several stations around the state is stifling. The high temperature average for Birmingham was 84.4° in October. The previous high was 83.0° ... in October 1919.
Anniston's average October high was 84.3°; the previous high was 81.8° in October 1963. The 83.9° October average in Muscle Shoals was a bit under its record-setting 84.3° average in October 1963.
There have been some temperature extremes in past Alabama Octobers, including a 103° day in Troy on Oct. 5, 1954. That was a hot week. Within a day or two either side of Troy's October record, it hit 100° in Greensboro, Montgomery and Selma, and 99° in Anniston and Talladega.
But by the end of that October, temperatures fell to near (or below) seasonal norms. The average highs for October 1954 were warmer than normal, but nothing like what we recorded this fall.
Of course, the drought and heat wave are having widespread effects across the state. Some streams and creeks that normally have low flows this time of year are completely dry, and there are concerns about the survival of aquatic species that exist in only a few watersheds in Alabama.
The Little River in northeastern Alabama has no water running over the waterfalls in the national park there. USGS records show this is the first time that has happened since record keeping started in the late 1950s. The lowest flow there previously was about one tenth of a cubic foot of water per second in the early 1960s.
While farmers, orchard keepers and others have been hit by the drought, the biggest impact we see is on livestock farmers. Their pastures die when there is two months of drought, so they face the dilemma of deciding whether to sell livestock in a saturated market or importing hay to get them through the winter.
- John Christy