Climate and Weather Monitoring at Sand Creek Massacre National Historic Site: Water Year 2022

Heavy rain falls to the west of Sand Creek.

NPS

Overview

Together, climate and hydrology shape ecosystems and the services they provide, particularly in arid and semi-arid ecosystems and across the Southern Plains (Woodhouse and Overpeck 1998). Understanding changes in climate, groundwater, and surface water is key to assessing the condition of park natural resources—and often, cultural resources.

At Sand Creek Massacre National Historic Site (Figure 1), Southern Plains Network scientists study how ecosystems may be changing by taking measurements of key resources, or “vital signs,” year after year—much as a doctor keeps track of a patient’s vital signs. This long-term ecological monitoring provides early warning of potential problems, allowing managers to mitigate them before they become worse. At Sand Creek Massacre National Historic Site, we monitor climate among other vital signs.

Reporting is by water year (WY), which begins in October of the previous calendar year and goes through September of the water year (e.g., WY2022 runs from October 2021 through September 2022). This article reports the results of climate monitoring at Sand Creek Massacre National Historic Site (Figure 1) in WY2022.

Reference: Woodhouse, C. A., and J. T. Overpeck. 1998. 2000 years of drought variability in the central United States. Bulletin of the American Meteorological Society 79(12): 2693–2714. https://doi.org/10.1175/1520-0477(1998)079%3C2693:YODVIT%3E2.0.CO;2

Figure 1. Weather station near Sand Creek Massacre National Historic Site.

NPS

Climate and Weather

There is often confusion over the terms, “weather” and “climate.” In short, weather describes instantaneous meteorological conditions (e.g., it’s currently raining or snowing, it’s a hot or frigid day). Climate reflects patterns of weather at a given place over longer periods of time (seasons to years). Climate is the primary driver of ecological processes on earth. Climate and weather information provide context for understanding the status or condition of other park resources.

Methods

A National Oceanic and Atmospheric Administration (NOAA) Cooperative Observer Program (COOP) weather station (Eads Colorado 052446) has been operational 15.5 mi (24.9 km) southwest of Sand Creek Massacre National Historic Site since 1907 (see Figure 1). This station provides a reliable, long-term climate dataset used for analyses in this report. Data from this station are accessible through Climate Analyzer.

Frost on the trees at Sand Creek Massacre National Historic Site.

NPS

Results for Water Year 2022

Precipitation

Annual precipitation near Sand Creek Massacre National Historic Site at the Eads station in WY2022 was 12.24″ (31.1 cm; Figure 2), which was 3.46″ (8.8 cm) less than the 1991–2020 annual average. March and July were both wetter than usual, receiving 1.23″ and 1.34″ more than the 1991–2020 monthly averages, respectively. Precipitation totals in January and May were similar to the 30-year average. All other months received substantially less precipitation than average, with no precipitation recorded at the weather station in November, December, and April. Extreme daily rainfall events (≥ 1 in; 2.54 cm) occurred on 2 days, near the average annual frequency of 2.7 days. Extreme rainfall events occurred on 22 March 2022 (1.06 in; 2.7 cm) and 25 July 2022 (1.70 in; 4.3 cm).

Air Temperature

The mean annual maximum temperature near Sand Creek Massacre National Historic Site at the Eads station in WY2022 was 69.9°F (21.0°C), 2.6°F (1.4°C) above the 1991–2020 average. The mean annual minimum temperature in WY2022 was 38.4°F (3.5°C), 0.9°F (0.5°C) above the 1991–2020 average. Average temperatures in October–December WY2022 were warmer than the 1991–2020 monthly averages (Figure 2) and differed by as much as 10.4°F (5.8°C; see December). This was followed by cooler than average temperatures in February and March. The rest of the year was similar to or warmer than the 30-year averages. Extremely hot temperatures (≥ 96°F; 35.6°C) occurred on 33 days in WY2022, more than the average frequency of 23.3 days. Extremely cold temperatures (≤ 10°F; -12.2°C) occurred on 28 days, more than the average frequency of 20.7 days.

Figure 2. Climogram showing monthly precipitation and mean maximum and minimum temperatures in water year 2022 and the 1991–2020 averages at Eads station near Sand Creek Massacre National Historic Site. Data source: climateanalyzer.org.

NPS

Drought

Reconnaissance drought index (Tsakiris and Vangelis 2005) provides a measure of drought severity and extent relative to the long-term climate. It is based on the ratio of average precipitation to average potential evapotranspiration (the amount of water loss that would occur from evaporation and plant transpiration if the water supply was unlimited) over short periods of time (seasons to years). The reconnaissance drought index for the Eads station near Sand Creek Massacre National Historic Site indicates that WY2022 was slightly drier than the 1991–2020 average, from the perspective of both precipitation and potential evapotranspiration (Figure 3).

Reference: Tsakiris G., and H. Vangelis. 2005. Establishing a drought index incorporating evapotranspiration. European Water 9: 3–11.

Figure 3. Reconnaissance drought index for the Eads station near Sand Creek Massacre National Historic Site in water  years 1991–2022. Drought index calculations are relative to the time period selected (1990–2022). Choosing a different set of start/end points may produce different results. “N/A” = insufficient data to generate reliable estimates. Data source: climateanalyzer.org.

NPS

---

Go to
Climate and Weather
Back to Top

---

Authors: Kara Raymond, Andy Ray

Please cite this report as
Raymond, K., and A. Ray. 2024. Climate and Weather Monitoring at Sand Creek Massacre National Historic Site: Water Year 2022. Southern Plains Network, National Park Service, Pecos, New Mexico.