ABRFC 2023 Year in Review

The ABRFC basin saw a slightly above average year of rainfall in 2023. The western half of the area saw above average rainfall, with a wide swath receiving nearly double the amount of typical annual rainfall from Colorado and Southwest Kansas into the Panhandles. Within this area, locations received over 6-12 inches more than normal. In July, numerous thunderstorm complexes tracked over these areas each day for almost a week straight. This created drought improvement and drought removal in many areas. Southeast Kansas into Northeast Oklahoma as well as North Central New Mexico and Southwest Oklahoma saw below average rainfall amounts between 50-75% of the usual totals. Parts of Southeast Kansas remained in Exceptional (D4) Drought for a majority of the year, after receiving between 15-20 inches less than average. For a transition to an El Niño year, which trends much wetter than average, 2023 underperformed but still accomplished a wetter than average year across the western half of the basin and the extreme southeast.

The drought conditions improved drastically from the start of the year. A majority of Kansas and a good portion of Oklahoma was experiencing Extreme (D3) to Exceptional (D4) Drought. However, by the end of 2023, most of those areas were either drought free or in a much lower drought category. Impacts of moderate to severe drought still remain in 26% of the basin. Only a small part of Central Kansas (in Rice and Reno Counties) remained in Extreme Drought. Areas of New Mexico and Central Arkansas received a worse drought category compared to the start of 2023 but none worse than Severe Drought (D2).

The snowpack in Colorado and New Mexico as a whole was around average. Despite an average snowpack, the seasonal runoff was below average for both the Arkansas and Canadian River Basins, due to a very dry fall that dried out the soil. As a result, the snowpack infiltrated into the ground for a much longer duration before runoff began. The following images from the National Operational Hydrologic Remote Sensing Center (NOHRSC) show the peak snowpack for the Spring 2023 season. Snowfall was above average along the continental divide and in parts of Northern New Mexico. The areas below average were near the New Mexico/Colorado state line and east away from the continental divide. Pikes Peak had very low snowpack this season.

For the Spring 2024 season as of December 31st, an entire area is seeing a below average snowpack, with the exception of near Taos, New Mexico as slightly above average. However, snowpack season is just beginning and the bulk of the snowpack builds between January and March.

A heavy rain event began across Southeast Oklahoma and Western Arkansas on February 7th, where more than 3 inches fell in these locations. The deluge continued moving to the east on February 8th, with the heaviest rains impacting mainly Arkansas. Storm totals from this event ranged from 3-7 inches. Ordinarily, an event that included this much rainfall would produce some minor river flooding but a flood of this magnitude was unusual. The two key factors that led to this rain producing widespread flooding concerns were the dormant vegetation and a sleet and ice event a few days prior.  Between Jan. 30-Feb. 3 , a significant ice storm produced around 1 inch of sleet and 0.25-0.50 inches of freezing rain in the same areas as the highest rainfall fell. This amount of ice and sleet created a "concrete-like" frozen ground layer that was present during the heavy rainfall and forced the water to runoff into rivers and streams instead of infiltrating into the soil. Many severe river flooding events in the winter months involve a melting snowpack, or in this case, a thick layer of ice and sleet.

After a wet February, March started out very wet with another heavy rain event on March 2nd-3rd in a similar location to the February event. A rapidly strengthening low pressure system developed over Texas on March 2nd, moved into Arkansas overnight, leading to the lowest barometric pressure ever recorded in North Little Rock: 29.07 inHg or 984 mb ( NWS Little Rock ). The combination of heavy rain on saturated and rocky soils resulted in substantial runoff into rivers and streams. In particular around Danville, Arkansas, over 6 inches of rain was reported and caused the Petit Jean River to crest in Major Flood Stage and have a top 10 crest in reported history and is the 5th highest since Blue Mountain Lake was completed in 1947.

A very wet pattern emerged across Far Eastern New Mexico, Southeast Colorado and the Texas/Oklahoma Panhandles in the last week of May and lasted through the first few days of June. Persistent favorable atmospheric conditions with a stationary upper low over Arizona and an upper level high centered over South Central Texas allowed for high amounts of Gulf of Mexico and Pacific moisture for an unusually long period of time. Multiple rounds of thunderstorms caused serious flash flooding and significant river flooding. Over Memorial Day weekend alone, this region saw 5-7 inches of rainfall which is nearly one third the yearly total rainfall in this area (15-20 inches per year). Many river forecast points in the Texas Panhandle crested in Action Stage or higher.

The heavy rains filled up multiple reservoirs that were either far below normal or completely dry. Buffalo Lake, southwest of Canyon, Texas filled up after being completely dry a month prior. The auxiliary spillway for Buffalo Lake was utilized for the first time in years. The level of Lake Meredith on the Canadian River rose 9 feet in the span of a month from this event.

Flows from severe New Mexico and Western Texas Panhandle flooding routed down the Canadian River from areas near Ute Dam near Logan, New Mexico through the Texas Panhandle in about 5-6 days. The sheer amount of water from upstream combined with the water from local rains pushed the Canadian River at Amarillo (19N) to Moderate Flood Stage for the first time in 42 years.

ABC7 Amarillo Article:  https://abc7amarillo.com/news/local/historic-rains-fuel-canadian-river-flooding-minor-flooding-lake-meredith-texas-panhandle-more-rain-on-the-way 

State Disaster Declaration:  https://gov.texas.gov/news/post/governor-abbott-issues-disaster-declaration-for-northwest-texas-flooding 

Flooding pictures from Boys Ranch upstream from the Amarillo forecast location:  https://twitter.com/NWSAmarillo/status/1663310648149962752 

Spring of 2023 brought rare events to the ABRFC in other western areas as well, due to the aforementioned atmospheric pattern. For much of May, potent thunderstorms were beginning to saturate the ground, especially in southeast Colorado, resulting in high flows along the upper Arkansas River above Pueblo Dam and elsewhere.

On June 12th, heavy storms near the headwaters of Fountain Creek caused several sites to reach near or above flood stage, including at Fountain, CO where moderate flooding occurred (see hydrograph below). This water then drained to the Arkansas River just downstream of Pueblo Dam. The combination of high flows already present on the Arkansas River, along with the high flows from Fountain Creek, ultimately pushed the Arkansas River near Avondale slightly above major flood twice on June 13th. Unfortunately, heavy storms occurred along Fountain Creek on June 22nd as well, resulting in higher flows near flood stage once again, especially at Fountain and Pueblo, CO (see hydrographs below). These flows, when combined with the higher flows still present on the Arkansas River, ultimately pushed the river near Avondale to roughly 1.5 feet above major flood, with minor flooding downstream at Nepesta and La Junta, CO (see hydrographs below). Following each major flood, surveys revealed there was little to no damage observed. As a result, analyses have been done to redefine the flood stages of the Arkansas River near Avondale.

Colorado Springs Flood  https://gazette.com/weather/colorado-springs-area-rain-totals-for-june-12-2023/article_404ad174-0977-11ee-a723-3fbd95343465.html   https://gazette.com/weather/colorado-springs-weather-updates-emergency-lane-closure-on-i-25-after-heavy-rains-cause-slope/article_42ad468a-0919-11ee-b256-634fc438d449.html  Federal Emergency Declaration  https://mars.colorado.gov/DR4731 

During the first half of July, many thunderstorm complexes (Mesoscale Convective System or MCS) moved over the same areas from Southeast Colorado through Southwest Oklahoma. MCSs are a common occurrence in the late spring and summer months and do not typically cause a substantial river flood risk if only one occurs. However, due to an upper-level blocking pattern and a stationary front at the surface, at least one of these storm systems per day over a 5 day period tracked over the same areas. 6-10 inches of rain in 5 days led to soils becoming very saturated and widespread river flooding ensued. The Cimarron River and Canadian River basins were most affected. Some locations in Western Oklahoma have not seen this magnitude of river flooding in 15-20 years. With the region being rural, mainly agricultural impacts were observed. The U.S. Drought Monitor showed rapid improvement across portions of this region after the rainfall event. Most locations saw a 1-2 category improvement over the course of a week, including areas that saw drought removal.

On October 25th, the Neosho River at Neosho Rapids, Kansas crested at 19.76 ft after receiving over 8-10 inches of rain in the basin. On December 24th, the Neosho Rapids forecast point crested at 18.38 ft after receiving only 3 inches of rain.

The difference was the ongoing drought in most of Eastern Kansas starting in 2022 and lasting through October 2023. The Neosho River basin was placed in Extreme (D3) Drought on the October 24th analysis. Soil moisture before the October storm was severely depleted, leaving ample room for the water to be absorbed into the soil.

On the morning of Oct. 25th, a training line of storms developed and dropped 4-10 inches over Chase and Lyons counties in Kansas. The soil in this area became waterlogged due to the amount of rainfall in a short period of time. However, the water was quickly absorbed into dry soil and did not runoff into the rivers as much had it been wetter previously. Despite that, there was still enough water that ran off into the rivers to cause an Action Stage crest.

With much higher soil moisture and dormant vegetation in December, between 2-3 inches of rainfall caused nearly the same amount of water to runoff into the rivers. Rainfall is an important factor that can cause river flooding but is not the sole aspect as seen in this example.

Advanced Hydrologic Prediction Service (AHPS)

Dominic Paoletti, Mason Rowell and NWS ABRFC

Justin Louen and NWS Pueblo

Lance Goehring and NWS Amarillo:  https://www.weather.gov/ama/LateMay-EarlyJune_HistoricalFlooding 

National Drought Mitigation Center (NDMC)

National Operational Hydrologic Remote Sensing Center (NOHRSC)

NWS Little Rock:  https://www.weather.gov/lzk/2023a.htm