Status and Climate Applications of the 19th Century Forts and Volunteer Observer Database

The Climate Data Modernization Program Forts and Volunteer Observer Database (CDMP-Forts) currently consists of 450 keyed and 355 quality-controlled stations for the period 1788–1892, reaching across the United States. In conjunction with the Global Historical Climate Network (GHCN) daily data, this resource is invaluable for examining 19th century weather and climate in the United States. CDMP-Forts is incomplete, however, with a considerable amount of data remaining to be digitally transcribed and quality controlled. It is the intent of this paper to provide an overview of the processes involved in rescuing these data and to show important ways these data can be used and the considerations that may have to be taken to create meaningful analyses. Finally, the dataset is placed in the context of other global datasets and efforts to rescue historical weather data.

Making sense of flash drought: definitions, indicators, and where we go from here

The topic of “Flash Drought” is rapidly gaining attention within both the research and drought management communities. This literature review aims to synthesize the research to-date and provide a basis for future research on the topic. Specifically, our review is focused on documenting the range of definitions of “flash drought” being proposed in the research community. We found that the term first appeared in the peer-reviewed literature in 2002, and by 2020 has become an area of active research. Within that 18-year span, “flash drought” has been given 29 general descriptions, and 20 papers have provided measurable, defining criteria used to distinguish a flash drought from other drought. Of these papers, 11 distinguish flash drought as a rapid-onset drought event while eight distinguish flash drought as a short-term or short-lived, yet severe, drought event and one paper considers flash drought as both a short-lived and rapid onset event. Of the papers that define a flash drought by its rate of onset, the rate proposed ranges from 5 days to 8 weeks. Currently, there is not a universally accepted definition or criteria for “flash drought,” despite recent research that has called for the research community to adopt the principle of rapid-intensification of drought conditions.

The flash drought of 1936

An exceptional flash drought during the spring and summer of 1936 led to extreme heat waves, large losses of human life and significant reductions of crop production. An analysis of historic precipitation and temperature records shows that the flash drought originated over the southeastern United States (U.S.) in April 1936. The flash drought then spread north and westward through the early summer of 1936 and possibly merged with a flash drought that had developed in the spring over the northern Plains. The timing of the flash drought was particularly ill-timed as most locations were at or entering their climatological peak for precipitation at the onset of flash drought, thus maximizing the deficits of precipitation. Thus, by early July most locations in the central and eastern U.S. were either in drought or rapidly cascading toward drought. The weeks that followed the 1st of July were some of the hottest on record in the U.S., with two major heat waves: first over the Midwest and eastern U.S. in the first half of July and then across the south-central U.S in the month of August. The combination of the flash drought and heat wave led to an agricultural disaster in the north central U.S. and one of the deadliest events in U.S. history.