USDA/NASS Disaster Analysis Web Page https://www.nass.usda.gov/Research_and_Science/Disaster-Analysis/index.php Synopsis Event: Western Drought and Extreme Heat Analysis - Summer 2021 Last Updated: September 10, 2021 Assessment Period: Week 35 (Aug 30-Sep 5, 2021) NOTE: Week 35 is the last planned weekly report in this series ------------------------------------------------------------------------- ------------------------------------------------------------------------- File: 2021_Western_Drought_And_Extreme_Heat_Analysis_Week35_Aug_30-Sep_05_2021_report.pdf Description: This report shows detailed drought, heat, and precipitation data in response to the drought conditions and extreme heat over the western U.S. in July/August/September 2021. -------------------- PRISM Climate Group Temperature and Heat Anomaly Data Source: https://prism.oregonstate.edu/mtd/ Assessment Period: September 1-8, 2021 This data offers an "early glimpse" version of precipitation and temperature data from the current month. The datasets are modeled using climatologically-aided interpolation (CAI), which uses the long-term average pattern (i.e., the 30-year normals) as first-guess of the spatial pattern of climatic conditions for a given month or day. Data supported by USDA RMA. -------------------- Heat Stress Data Source: NASS Climate-based Information System Data calculated using data from two main sources of gridded products, PRISM, and RTMA. Heat stress is calculated as the difference between the maximum observed temperature during the day and the selected threshold (Tdth). HSDD = {(Tmax - Tdth) if Tmax >= Tdth, 0 otherwise} -------------------- Soil Moisture Data Source: Crop-CASMA - https://nassgeo.csiss.gmu.edu/CropCASMA/ Data: Sub Soil Moisture, 9km, Weekly, Year 2021, Week 35, August 30-September 5, 2021 Sub Soil Moisture Anomaly, 9km, Weekly, Year 2021, Week 35, August 30-September 5, 2021 Sub Soil Moisture Categorical, 9km, Weekly, Year 2021, Week 35, August 30-September 5, 2021 Sub Soil Moisture Definition: NASA Remotely Sensed Rootzone Soil (sub soil) is defined as the top 3.2 feet (approximately 1 meter). The NASA SMAP (Soil Moisture Active Passive) 9km soil moisture measurements are volumetric soil moisture (i.e. volumetric water content in the soil). It is simply the ratio of water volume to soil volume. Sub soil moisture measuring at 0.1 cm3/cm3 and below (10% water content) could be considered very dry. Sub Soil Moisture Anomaly Definition: The soil moisture anomaly (SMA) in CropCASMA is a measure of deviation of the current soil moisture value from the "normal" soil moisture level, which is represented by a historical average soil moisture value (from 2015 to current). Soil moisture anomaly below -40% could be considered very abnormal, which means there is 40% less soil moisture than normal conditions. Sub Soil Moisture Categorical Definition: SMAP values are categorized into NASS categories which include: Very Short - Soil moisture supplies are significantly less than what is required for normal plant development. Growth has been stopped or nearly so and plants are showing visible signs of moisture stress. Under these conditions, plants will quickly suffer irreparable damage. Short - Soil dry. Seed germination and/or normal crop growth and development would be curtailed. Adequate - Soil moist. Seed germination and/or crop growth and development would be normal or unhindered. Surplus - Soil wet. Fields may be muddy and will generally be unable to absorb additional moisture. Young developing crops may be yellowing from excess moisture. Crop mask and total cropland derived by 2020 Cultivated Layer hosted on Crop-CASMA. --------------------