Mapping the US Drought

The New York Times has published an interesting animated map to visualize the spread of drought conditions in the US over the last five months. Mapping the Spread of Drought Across the U.S. includes a number of weekly updated charts with an animated map to show the latest extent of the drought in the western and south-western states.

The map animates through the last five months showing heat maps of where the drought has been most severe. I'm not entirely sure how the map was created but based on the Mike Bostock credit I'm assuming the map was created with d3, using SVG to draw the map and the drought areas. The map may also be using path transitions to help smooth the animations between the different drought by date SVG paths.