Straddling the border with Mexico along the Rio Grande, the city of Laredo, Texas, and its 260,000 residents don’t just have to deal with the region’s ferocious heat. Laredo’s roads, sidewalks, and buildings absorb the sun’s energy and slowly release it at night, a phenomenon known as the urban heat island effect. That can make a hot spell far more dangerous than for people living in the surrounding countryside, where temperatures might stay many degrees cooler. The effect partly explains why extreme heat kills twice as many people each year in the United States than hurricanes and tornadoes combined.
To better understand how this heat island effect plays out in Laredo, the nonprofit Rio Grande International Study Center partnered with the National Oceanic and Atmospheric Administration last summer and enlisted more than 100 volunteers to drive around the city taking temperature readings. Edgar Villaseñor, the center’s advocacy campaign manager, worked with a company called CAPA Strategies, which created the map below. (Red shows where it’s hottest in the afternoon and blue where it’s coolest — notice the... Read more
