July-Aug 2002

Heat, cold, and desert humidity: UCAR writer pens book about weather patterns across the world

A connoisseur of wine might characterize a particularly good vintage as lively or full-bodied; a connoisseur of art might describe a Reubens masterpiece as incorporating aspects of classical sculpture. Then there's a different type of enthusiast, one who bundles up in rain gear and drives toward ominously dark thunderheads to enjoy the magnificence of a summer storm.

Bob Henson. (Photo by Carlye Calvin.)

Bob Henson of the UCAR Communications office—veteran storm chaser, weather photographer, and meteorologist—falls in the latter category. The winds, lightning, hailstones, and torrential rains that drive many of us inside have proved a powerful magnet for the UCAR Quarterly editor ever since his boyhood in Oklahoma City. "Surrounded by wild weather, I grew up fascinated by it," he explains on his Web page.

Now Bob has published an engaging book about weather across the world, The Rough Guide to Weather. It examines weather in every country, as well as discussing topics ranging from the history of meteorology to global climate change. The generously illustrated book also showcases the photographic talents of several staffers, including Bob, SN Monthly photographer Carlye Calvin, RAP's Greg Thompson, and CGD's Caspar Ammann.

In a recent talk and book signing at the Mesa Lab, Bob took the audience on a global tour of the vagaries of weather, looking at topics like heat, rain, and such meteorological eccentricities as humidity in a desert. He also shared stunning pictures of supercells, hailstorms, and other weather events.

"It's a big world," he said at the beginning of his talk. "There's a lot of weather in it."

And the weather is far more variable than many of us realize. Of course, there are the familiar parameters, like heat (El Azizia, Libya, holds the all-time record: 136° F, or 58° C), cold (Vostok, Antarctica, à129° F, or 89° C), and rain (Lloro, Colombia, received an estimated 523.6 inches, or 13,299 mm, in a single year).

But weather also holds subtle pleasures. For those who love buying lots of clothes, Bob notes that an especially "wardrobe-intensive climate" is Verkhoyansk, Russia, with average winter lows of à54° F (à48° C) and summer highs that typically climb to 69° F (21° C). On the other end of the spectrum is the mild climate of Nairobi, with typical highs hovering about 71° F (22° C) and lows about 54° F (7° C). "You might call it a springtime-all-year climate," Bob said.

Another unusual destination is the Pacific coast of Colombia, where some areas receive as much as 390 inches (10,000 mm) of annual rain—much of which falls during the night, leaving plenty of days sunny. "If you want a lot of rain, but you also want to get out and do stuff, head for Colombia," Bob advised.

A twist on desert weather may be found in coastal Namibia, which gets little rain but has high humidity. The reason? The cool ocean currents just off the coast keep the air stable year round. "It doesn‚t rain much there at all, but it's kind of a cool, moist feel with a lot of humidity," Bob explained.

Bob suggested that people who don‚t like heat and humidity should stay away from Muscat, Oman, in June. Although extreme heat typically corresponds with lower humidity, temperatures in Muscat in June regularly soar to 102° F (89° C) with an average afternoon relative humidity of 43%—far higher than ever seen when such heat strikes Boulder.

What if you want all your rain to fall during just one part of the year? Consider visiting a monsoon city, such as Bombay, which typically gets deluged with 25.5 inches (650 mm) of rain in the wettest montḥand no precipitation at all in the driest. That's a far cry from a place like Montreal, where the rainfall every month averages 2.5à3.5 inches (66à91 mm).

So now that Bob has charted the weather for world travelers, is there another book project in the wings? After juggling the Rough Guide and UCAR work for many months, he says, "Right now it‚s nice to be back to working regular hours." And, he adds, "going on the occasional storm-chasing trip." • David Hosansky

Bob Henson's photo of a storm over Boulder is on the cover of his book. A look at some wild weather: Aridity: Few places are as dry as Chile's Atacama Desert, where Arica averages less than 0.004 inches (1 mm) of annual rainfall. But the champion of dryness may be Antarctica, where some areas haven't seen measurable precipitation for millennia. Daily variation: An arid climate and strong tropical sun can make for unusually hot days and chilly nights in Bolivia‚s Altiplano, a vast plateau where temperatures have spanned an astounding 75† F (42† C) in a single day. Cold: Large bodies of water typically moderate temperatures, so it may come as no surprise that Siberia's vast Lake Baikal has a slight warming impact on nearby areas during winter months. What's unusual is that the warmth percolates up through the frozen lake surface. Hail: The area around Kericho, Kenya, is one of the world's most hail-prone, recording some 100 days of hail in an average year. Fortunately the stones are generally small (at least by Colorado standards) and the hailstorms scattered. Topography: High altitudes are usually associated with colder temperatures. But the situation is reversed during winter in Switzerland‚s Mittelland Valley, where Siberian air masses chill the valley floor for weeks at a timẹwhile skiers thousands of feet higher may be basking in sunshine and temperatures as much as 18† F (10† C) warmer. A similar effect can occur along the Front Range when a cold, cloudy Arctic air mass slides into Boulder while Nederland stays bright and mild.

Edited by David Hosansky, hosansky@ucar.edu
Prepared for the Web by Carlye Calvin
Last revised: Mon Aug 19 17:08:40 MST 2001