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In Brief: Nights are warmer than they were in the early 1970s, which exacerbates the urban heat island effect and heat related health problems. Heat waves, which in the United States kill up to 1,000 people per year, are defined as prolonged periods of abnormally hot weather. They can occur at any time of the [...]

The torrential rainfall and storm surges associated with hurricane landfall events can cause what are known as “overwash deposits” that leave definitive marks in the sediment layers that accumulate in coastal areas. Analyses of sediment cores from various locations along the Eastern Seaboard and Puerto Rico show that for the last 1500 years, Atlantic Hurricanes [...]

Over the second-half of the 20th century, the Southeast experienced an overall decline in annual rainfall levels along with a 20 percent increase in the frequency of extreme (top first percentile) rainfall events. Looking at the 20th century as a whole, there have been significant changes in the seasonal distribution of precipitation, with strong increases [...]

Many of America’s most important commercial crops require between 400 and 1800 hours each winter when the temperature is below 45 degrees Fahrenheit. Winter temperatures have been rising steadily across the nation, with the most pronounced trends being witnessed in the upper-Midwest and Northeast. In fact, winter temperatures are rising faster than temperatures in any [...]

In North America over the last 50 years, average nighttime low temperatures have risen faster than average daytime high temperatures. There has been a 50 percent increase in the number of unusually warm nights and nights that fell into the top tenth percentile in terms of temperature for the climate of the 1950′s now fall [...]

About 75 percent of the West’s water resources originate in snowpack. Most precipitation in the region occurs during the winter, the period of the year when the reservoirs are replenished after the dry summer and early fall months. The reservoirs are at their high points in the spring. Traditionally, snowpack would last into the late [...]

Most areas of the United States are now receiving more total annual rainfall than they did 50 years ago. There is significant regional variability in this trend, however. Adding up the total regional positive and negative trends, the U.S. as a whole is now receiving five percent more precipitation each year. The Northeast and northern [...]

Most areas of the United States are now receiving more total annual rainfall than they did 50 years ago. There is significant regional variability in this trend, however. Adding up the total regional positive and negative trends, the U.S. as a whole is now receiving five percent more precipitation each year. The Northeast and northern [...]

Most areas of the United States are now receiving more total annual rainfall than they did 50 years ago. There is significant regional variability in this trend, however. Adding up the total regional positive and negative trends, the U.S. as a whole is now receiving five percent more precipitation each year. The Northeast and northern [...]

While global sea-level is rising at a rate of about 1.2 inches per decade due to an influx of glacial melt water and thermal expansion of the oceans, the relative sea-level rise or fall that each coastal location experiences is dependent on several factors. Local sea-level can rise faster than the global average due to [...]

While global sea-level is rising at a rate of about 1.2 inches per decade due to an influx of glacial melt water and thermal expansion of the oceans, the relative sea-level rise or fall that each coastal location experiences is dependent on several factors. Local sea-level can rise faster than the global average due to [...]

While Phoenix has always been hot for U.S. standards, over the last 50 years the city has been getting even hotter. The average number of days per year when the temperature is over 100 degrees has doubled over this time period. Part of this is likely due to the Urban Heat Island effect, which has [...]

Most areas of the United States are now receiving more total annual rainfall than they did 50 years ago. There is significant regional variability in this trend, however. Adding up the total regional positive and negative trends, the U.S. as a whole is now receiving five percent more precipitation each year. The Northeast and northern [...]

As Earth warms, the water cycle intensifies. While this means more total rainfall for some regions, it also means that more rainfall comes in the form of heavy and extreme events and periods between rainfall events become longer. Longer periods without rain and higher temperatures lead to losses of soil moisture; if drying of the [...]

Heat waves, defined as three or more consecutive days when temperatures exceed 90 degrees Fahrenheit, can create public health hazards. In the United States, heat and drought account for the biggest share of hazard-related deaths at 19.6 percent. Death rates rise an average of six percent during heat waves and over the 20th century, the [...]