Currents Archive

Early snowmelt risk: Photo of daffodils amid late-winter snow in West Virginia Bob Henson • March 27, 2014 | At some point in a typical winter, almost half of the entire Northern Hemisphere’s land area is plastered with snow cover. You’d expect that snow to disappear in the spring, and, even after this unforgiving U.S. winter, most of it will. However, in recent years, spring snow has been vanishing even more quickly than computer models and climate scientists had expected.
Plowing snow in New Hampshire: How do cold winters and climate change intersect? Bob Henson • March 5, 2014 | Even as frigid air kept parts of the Midwest and Northeast in a headlock, the remarkable meteorological winter of 2013–14 ended on Friday. That’s based on how weatherpeople define the season in the Northern Hemisphere: December through February, which are the three coldest months of the year in most mid- and high-latitude areas. So perhaps now is a good time to start putting this memorable period in our rear-view mirror.
Midwest cold wave: Ice fog in frigid air produces sun dogs Bob Henson • January 14, 2014 | Last week’s Arctic outbreak brought some of the coldest air in decades across the Midwest and South. But interestingly, it didn’t last long. The graphics below show the number of consecutive days during this month’s cold snap that temperatures stayed below freezing (midnight to midnight) in New York, Atlanta, and Chicago. In each case, the temperatures moderated far more quickly than was the case during some of the most intense cold waves of the last 40 years.
Drought puts California water supply at risk: Photo of Lake Mead, Nevada/Arizona Bob Henson • January 13, 2014 | The first precipitation measurements in what’s now downtown San Francisco began in July 1849, a year before statehood. Now extending almost 165 years, the local rainfall database is one of the nation’s longest—and never has it shown a year as dry as 2013.
Warming hiatus? Map showing changes in global temperature since late 1970s Bob Henson • January 8, 2014 | The globally averaged surface air temperature hasn’t risen much in the last 15 years. But as a fresh batch of research has made clear, there’s been ample heating of Earth—which becomes evident when looking at certain times of the year and in particular locations, including deep in the ocean.
Winter cold: Student launching a weather balloon in heavy snow during OWLes project Bob Henson • January 6, 2014 | It’s hard to escape the cold weather now plowing into the eastern United States—especially if you turn on a TV or log onto Facebook. The big freeze is a compelling news story, with truly dangerous temperatures and wind chills extending into large swaths of the nation. Yet we’ve had worse: in some ways, this cold snap serves to illustrate how rare such intense events have become. Amid all the hype, what stands out about this early winter onslaught?
Snow and the Super Bowl: Chicago's worst blizzard struck in January 1967 If the official weather forecast holds, Sunday's Super Bowl won’t have to be postponed. But the outlook would be far more uncertain if predictions today were as primitive as they were at the time of the first Super Bowl in 1967.
Can a two-week forecast warn us of Super Bowl snow? Pictured: 1950 "Snow Bowl" Next month’s Super Bowl will be the first ever held in an open stadium in the northern United States. What weather might we expect two weeks from now, and how might research help improve a forecast in that time range?