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Strong winds blew across mountain slopes after a record-setting warm, dry summer. Small fires began to blow up into huge conflagrations. Towns in crisis scrambled to escape as fires bore down. This could describe any number of recent events, in places as disparate as Colorado, California, Canada and Hawaii. But this fire disaster happened over 110 years ago in the Northern Rocky Mountains of Idaho and Montana. The “Big Burn” of 1910 still holds the record for the largest fire season in the Northern Rockies. Hundreds of fires burned over 3 million acres – roughly the size of Connecticut – most in just two days. The fires destroyed towns, killed 86 people and galvanized public policies committed to putting out every fire. Many residents of Wallace, Idaho, fled on trains ahead of the 1910 blaze. Volunteers who stayed saved part of the town, but about a third of it burned. R.H. McKay/U.S. Forest Service...

Meteorologists have been talking for weeks about a snowy season ahead in the southern Rockies and the Sierra Nevada. They anticipate more storms in the U.S. South and Northeast, and warmer, drier conditions across the already dry Pacific Northwest and the upper Midwest. One phrase comes up repeatedly with these projections: a strong El Niño is coming. It sounds ominous. But what does that actually mean? We asked Aaron Levine, an atmospheric scientist at the University of Washington whose research focuses on El Niño. NOAA explains in animations how El Niño forms. What is a strong El Niño? During a normal year, the warmest sea surface temperatures are in the western Pacific and the Indian Ocean, in what’s known as the Indo-Western Pacific warm pool. But every few years, the trade winds that blow from east to west weaken, allowing that warm water to slosh eastward and pile up along the equator. The warm water causes...

If you have ever gotten a vaccine or received an intravenous drug and did not come down with a potentially life-threatening fever, you can thank a horseshoe crab (Limulus polyphemus). How can animals that are often called living fossils, because they have barely changed over millions of years, be so important in modern medicine? Horseshoe crab blood is used to produce a substance called limulus amebocyte lysate, or LAL, which scientists use to test for toxic substances called endotoxins in intravenous drugs. These toxins, produced by bacteria, are ubiquitous in the environment and can’t be removed simply through sterilization. They can cause a reaction historically referred to as “injection fever.” A strong concentration can lead to shock and even death. Identifying LAL as a highly sensitive detector of endotoxins was a 20th-century medical safety breakthrough. Now, however, critics are raising questions about environmental impacts and the process for review...

CC BY-ND Hardworking American farmers keep the world fed and clothed. But the farming labor force has a problem: It’s aging rapidly. The average American farmer is 57 and a half years old, according to the most recent data from the U.S. Department of Agriculture. That’s up sharply from 1978, when the figure was just a smidge over 50. As researchers who study well-being in rural areas, we wanted to understand this trend and its implications. So we dug into the data. Amber waves of graying We found that the average age of farmers was fairly consistent across the country, even though the general population’s age varies quite a bit from place to place. For example, the average Maine farmer is just a few months older than the average farmer in Utah, even though the average Maine resident is more than a decade older than the average Utahn. To be fair, we did find some local differe...

The Rio Grande is one of the longest rivers in North America, running some 1,900 miles (3,060 kilometers) from the Colorado Rockies southeast to the Gulf of Mexico. It provides fresh water for seven U.S. and Mexican states, and forms the border between Texas and Mexico, where it is known as the Río Bravo del Norte. The river’s English and Spanish names mean, respectively, “large” and “rough.” But viewed from the Zaragoza International Bridge, which connects the cities of El Paso, Texas, and Ciudad Juárez, Mexico, what was once mighty is now a dry riverbed, lined ominously with barbed wire. The Rio Grande is one of the largest rivers in the southwest U.S. and northern Mexico. Because of drought and overuse, sections of the river frequently run dry. Kmusser/Wikipedia, CC BY-SA In the U.S., people often think of the Rio Grande mainly as a political border that f...