U.S. Virgin Islands | Drought.gov

The United States Virgin Islands (USVI) is a small territory to the east of Puerto Rico that consists of three main islands—St Thomas, St Croix, and St John—and a few smaller, mostly unpopulated islands. Due to its geographical location in the center of the Caribbean, the USVI has two distinct seasons—the hurricane (wet) season from August to November and the dry season for the remainder of the year. Typically, about 40% of the annual rainfall occurs in the 3 wettest months, from September to November. Typical of many tropical islands, easternmost and leeward areas have the greatest aridity and sometimes feature vegetation (e.g., cacti) and landscapes (e.g., lack of trees) more typical of tropical dry forest and grasslands than a tropical rainforest.

Impacts from drought can be consequential since there are no significant sources of surface water (e.g., perennial rivers) and minimal groundwater due to the high relief of the islands. Most of the population draws their water from cisterns that collect rooftop water, and the rest are dependent on groundwater. Many must purchase water purified by reverse osmosis when there are no other sources. Drought also parches pastures and dries up ponds, which directly harms food and livestock production across the islands. With temperatures continuing to rise incrementally, future droughts should increase in number and be more impactful, with greater impacts on agriculture, water sources and community water collection in the territory.

NIDIS supports eight regional Drought Early Warning Systems (DEWS) throughout the United States. In addition, NIDIS supports states and territories outside these regions, like the U.S. Virgin Islands, by delivering drought early warning information through Drought.gov; investing in drought research to address key scientific and societal needs; and supporting the development of new tools and products that serve the entire nation.