For nearly 20 years, the U.S. Drought Monitor has provided week-by-week drought assessments for the continental United States, Alaska, Hawaii and, soon after the map’s debut, Puerto Rico. Over that time, advances in technology and an expanding network of local observers have helped make the map a key resource in triggering both drought-related disaster declarations and responses to drought from state, local, tribal and basin-level decision makers.
In April, for the first time since 2000, the USDM added a new collection of territories to the weekly map. The U.S.-affiliated Pacific Islands (USAPI) are now included in the weekly report of drought. The USAPI consist of three U.S. territories and three independent countries in free association with the U.S. The territories are American Samoa, Guam and the Commonwealth of the Northern Mariana Islands. The independent countries are the Federated States of Micronesia, the Republic of the Marshall Islands and the Republic of Palau.
Located in five time zones across an expanse of the Pacific Ocean larger than the North American continent, the USAPI are a collection of isolated islands that, as a 2017 U.S. Geological Survey report stated, “are generally perceived as having wet climates.” But the territories are also vulnerable to episodic drought, according to the report. Drought in the USAPI can lead to crop damage, wildfires and low stream outputs where streams exist, according to a report compiled by Richard Heim, a meteorologist with the National Climatic Data Center and one of the authors of the USDM.
On April 8, the USDM published a narrative of current drought conditions across the USAPI by Brad Rippey, a meteorologist with the U.S. Department of Agriculture. Rippey reported that while most of the southern and eastern islands are free of dryness and drought, low rainfall totals have led to drought conditions in the northern and western islands. According to Rippey, low rainfall totals across the Marianas have led to drought declarations in Saipan, Guam and Rota while a short-term drought across the Marshall Islands has left Utirik experiencing exceptional drought (D4-S).
Incorporating the USAPI into the U.S. Drought Monitor has been a project several years in the making. Starting this month, users of the USDM will be able to see if drought is impacting the territories as part of the weekly report. To see the latest USDM, go to droughtmonitor.unl.edu.
- By Cory Matteson, National Drought Mitigation Center Communications Specialist