National Climate Report - Annual 2018
US Drought in 2018
US Drought in 2018
The year 2018 was very wet, on average, for the United States. However, drought occurred across much of western and southern parts of the country. In much of the southwest, drought was persistent and severe. This dichotomoty - a wet year with significant drought - continued recent trends of increased extremes in the hydrologic (rain, runoff, evaporation) cycle. The following three graphics each provide a snapshot of U.S. drought during 2018, from three slightly different analysis perspectives. Each draws from the 52 weekly U.S. Drought Monitor assessments published during 2018. Click any of them for a much larger map that includes Alaska and Hawaii.
These maps were co-produced in cooperation with the U.S. Drought Portal.
Map: Weeks in drought
This map shows how many of the year's 52 weekly USDM analyses depicted drought, defined as category "D1 - Moderate Drought" or greater, for locations across the United States. Click for larger image that includes Alaska and Hawaii.
Map: Most intense USDM classification
This map depicts the most intense weekly USDM classification for locations across the United States, regardless of when that designation occurred. Click for larger image that includes Alaska and Hawaii.
Map: Cumulative drought intensity
This map depicts something of a integration of drought duration and intensity, tabulated over the course of the year. It was calculated by multiplying the USDM category (D0=0, D1=1, ..., D4=4) by the number of weeks designated in that category. For example, a location in D2 drought for 20 weeks and D1 drought for 5 weeks equals a cumulative intensity of 45 (20x2 plus 5x1). The maximum value possible is 208 (52x4). Note: this is not an official or widely-adopted product. Click for larger image that includes Alaska and Hawaii.