Precipitation Records and Anomalies for the U.S. in 2011
Precipitation Records and Anomalies for the U.S. in 2011
The past year saw some remarkable precipitation anomalies across the lower 48 states of the U.S. All-time wettest year on record was reported across a wide swath of the Ohio Valley and Northeast, while portions of Texas recorded their driest year on record. A few all-time state records for anomalous precipitation also occurred.
A very wet late winter and spring in the far West and Rocky mountains contrasted strongly to the driest such period on record for most of Arizona, New Mexico, and Texas. The Sierra Nevada of California and the Tetons in Wyoming both came close to breaking their all-time seasonal snow records with 800” accumulations. Seasonal snow records were also broken at Ely, Nevada (110.4”), Glasgow, Montana (108.6”), and Williston, North Dakota (107.2”). In May Billings, Montana shattered both its all-time wettest month on record with 9.54” (old record 7.71” in May 1981) and its 24-hour precipitation record with 3.35” on May 24-25 (old record 3.19” on April 27-28, 1978). These heavy rains and melting snows in the northern Rockies and Plains resulted in the record flooding along the Missouri and Mississippi Rivers and their respective branches during May and June.
During the summer the region of excessive rainfall moved eastward into the Upper Midwest and Ohio Valley. In July Dubuque, Iowa reported its wettest month on record with a 16.01” accumulation (old record 15.46” in September 1965) largely the result of its all-time greatest 24-hour rainfall of 10.62” on July 27-28 (old record 8.96” on August 21-22, 2002). Tropical Storms Irene and Lee at the end of August and beginning of September produced phenomenal amounts of rain in the Mid-Atlantic and Northeast resulting in numerous all-time monthly and 24-hour precipitation records:
Philadelphia, PA : Wettest month on record 19.31”.
New York, NY: Wettest month on record 18.95”.
Trenton, NJ: Wettest month on record 16.10”. The village of Stockton, about 15 miles north of Trenton, recorded 22.60” in August, shy of the all-time state monthly record of 25.98” at Patterson in September, 1882.
Newark, NJ: Wettest month on record 18.79” (unofficial record of 22.48” set in August 1843). On August 27-28 Tropical Storm Irene broke Newark’s all-time 24-hour precipitation record 8.92”.
Allentown, PA: Wettest month on record 13.47”.
September 4-5: Jackson, MS: all-time 24-hour rainfall 10.68”.
September 5-6: Chattanooga, TN: all-time 24-hour rainfall 9.50”.
September 7-8: Binghamton, NY: all-time 24-hour rainfall 8.70”.
Binghamton, NY: Wettest month on record: 16.58”
Texas Minimum Annual Precipitation Records for 2011
Meanwhile the drought intensified over Texas and portions of the Southern Plains reaching epic proportions in some areas. By the end of the year, however, late fall rains eased the drought situation for much of the region. Nevertheless, 2011 ended up being the driest year on record for Amarillo, Texas: 7.00” (former record 9.56” in 1969 and normal is 19.71”) and in Lubbock, Texas: 5.86” (former record 8.73” in 1917 and normal is 18.69”). The NWS also cited Laredo, Texas as having its driest year on record with a total of 6.66” (normal is 21.53”) although I can find a report of just 4.31” in the year of 1901.
Perhaps, most astonishing is the total annual rainfall of just 1.06” at Pecos, Texas (normal annual precipitation is 11.61”). If confirmed this would be a Texas state record for least amount of precipitation ever recorded in a calendar year, the current record stands at 1.64” at Presidio in 1956. In the 11-month period of Oct. 1, 2010 to Sept. 1, 2011, Pecos picked up just .03” of precipitation (actually the dry period was longer: from Sept. 23, 2010 to Sept. 13, 2011). See my from last June about how dry it was in Texas and the Southwest until the monsoon rains kicked in during August.
Drought Index at the peak of the summer in Texas. On July 12th a full 71% of the state was under ‘exceptional drought’ conditions.
List of Major U.S. Sites Recording their Wettest Year on Record in 2011
Below is a summary of all the major NWS sites that have so far confirmed having their wettest calendar year on record:
NOTE: For the beginning of record for the various sites listed I include Smithsonian and other pre-USWB records. Also, the ‘normals’ are for the 1971-2000 POR not the latest, still hard to find, 1981-2010 POR’s.
New York City’s Central Park location recorded 72.81” in 2011, its 2nd wettest year on record. The wettest year was supposedly 1983 when 80.56” was measured. However, this is a controversial figure since there were questions about the rain gauge’s condition that year. In fact, Newark (11 miles SW of Central Park) recorded just 65.50” in 1983 and La Guardia (5 miles east of Central Park) reported just 60.84” in 1983, so the 80.56” does seem suspicious.
Any State Precipitation Records Broken?
It will most likely take some time until all the COOP observer forms are in and calculated to determine if any all-time state precipitation records were broken in 2011. As I already mentioned, the preliminary 1.06” at Pecos would be a new dry record for a year in Texas.
In Ohio, the NWS office in Cincinnati has determined that 74.24” of precipitation fell in Cheviot, Hamilton County (just north of Cincinnati) breaking the former record of 70.82” at Little Mountain in 1870 (official state record) and the 72.08” at Mt. Healthy in 1880 (unofficial record). Other states to follow are Pennsylvania where 80.80” accumulated at Mt. Pocono in 2011 just short of the state record of 81.54” also at Mt. Pocono in 1952. Perhaps there may have been a wetter location this past year somewhere in the state.
Illinois bears watching as well, since Cape Girardeau on the border in Missouri recorded 74.51” and the Illinois record is 74.58” at New Burnside in 1950.
I will be curious how much precipitation fell at New York’s Slide Mountain site, the wettest location in the state and in the heart of the region (the Catskill Mountains) most affected by last year’s anomalous precipitation. Slide Mountain measured a state record of 90.97” in 1996, a tall order to beat.
In a similar vein Mt. Mansfield, Vermont measured a record 100.96” in 1996 and since most low-level sites in the state broke their record last year perhaps Mt. Mansfield did as well. Speaking of Vermont, there was an unofficial 11.23” of rain in a 24-hour period at Mendon, Vermont during the passage of Tropical Storm Irene in late August. The official 24-hour rainfall record for Vermont is 9.92” at Mt. Mansfield on September 17, 1999 (TS Floyd).
Mendon, Vermont was isolated for almost a week after TS Irene dumped over 11” of rain in 24 hours over the area. Photo by Vyto Starinkas/The Daily Herald.
As 2012 begins a possible drought is looming over California and, again, the Southwest. Snow depth in the Sierra Nevada is at its lowest on record for this time of year (early January) and no precipitation is in sight for the next two weeks.
Christopher C. Burt