April 29, 2010

The Boston Globe continues to post a huge number of pictures of the Icelandic volcano. Click here to have a look. What gorgeous sights.

April 23, 2010

Did you see the images on television last night of snowplows removing hail (not snow – HAIL!) from the highways in Colorado? And if you click here you’ll see video of a tornado that touched down in Texas last night.

There are strong thunderstorms predicted throughout this weekend in the Eastern two-thirds of the US, and Tornado Watches are in effect for communities that regularly experience these violent storms.

Why is all this happening at once? Well, it’s April, and that generally marks the beginning of the tornado season in the U.S.

A tornado’s funnel looks like a huge elephant’s trunk hanging down from a cloud. The funnel acts like a giant vacuum cleaner…whenever the “hose” touches the ground, it sucks things up into the air.

 Usually, tornadoes are local storms. A typical tornado is only 400 to 500 feet wide, has winds of less than 112 miles per hour, and last only a few minutes. But sometimes, monster tornadoes a mile wide with winds up to 500 miles per hour are born in very large thunderstorms – also called supercells – and they can cause tremendous destruction. Tornadoes have moved houses down a whole block, bounced 20-ton tractor-trailers up and down on the highway, even picked up a pond full of frogs and rained them down on a nearby town!

If you live near an area that is prone to tornadoes at this time of year, the most important things to remember are:

·      Pay attention to early warning sirens and alerts on radio and television, so that you can take shelter before a tornado strikes.

·      Cars and mobile homes are NOT safe during a tornado. Go to the basement of a solidly built house.

·      If you are in an apartment or home without a basement, getting into a bathtub and covering yourself with a couch cushion protects you on all sides.

·      If you are out walking or biking, life flat in a ditch if there is no rain. If there is rain, there may be a danger of flash flooding, so stay out of the ditch, get away from trees and power lines, crouch down and make yourself as small as possible - be a "human basketball"!

You don’t have to worry too much in advance about tornadoes, but finding out when they are coming and knowing what to do is certain to help you if one strikes.     

April 19, 2010

Our Planet Earth is putting on quite a show in celebration of the 40th Anniversary of Earth Day! For those interested in seeing photographs, the Boston Globe.com ran a feature this weekend with twenty striking images of the volcano, including shots of people on cross country skis taking photographs at the edge of the hot lava. Talk about a study in contrasts!

 The volcano continues to erupt in Iceland,  and air travel is still disrupted in northern Europe and Great Britain. If you look at this satellite image, you can see why:

The land mass at the top/left of the photo is Iceland. The two land masses at the bottom/center of the photo are Ireland and Britain. You can see why no planes are flying out of England - the country is enveloped in volcanic ash.

This volcano has not been studied extensively, so scientists do not know how long the eruptions might continue. From what has been observed so far, there will not be a significant impact on Europe’s weather. It takes a very big volcanic event to impact weather across a continent, or across the globe. When Mount Pinatubo erupted in the Phillippines on June 15,  1991, scientists   estimated that 20-million tons of sulfur dioxide and ash particles   blasted more than 12 miles high into the atmosphere. The eruption caused widespread destruction and loss of human life. And, the gases and solids injected into the stratosphere enveloped our globe for three weeks.That volcano caused an average 10% drop in temperatures,  affecting the world’s weather that year.

The eruption of   the Tambora volcano in 1815 (in what is now Indonesia) was one of the biggest weather influencers ever, triggering the famous Year   without a Summer in 1816. 

Scientists do not agree on whether even a huge volcanic eruption (much bigger than the one we’re experiencing this week) could ever have a long-term impact on climate.

Remember, weather is different from climate. When you talk about weather, you are talking about       what is happening in the atmosphere that day in a particular location. Weather tells...

April 15, 2010

In Iceland today, hundreds of people have been evacuated as floodwaters rise from the eruption of the volcano under the Eyjafjallajokull glacier. This is the second time it has erupted in less than a month. As water gushed down the mountainside, rivers had risen up to 10 feet by Wednesday night.

The volcano’s smoke and ash poses a threat to aircraft because it can affect visibility,  and microscopic debris can get sucked into airplane engines and can cause them to shut down. Airports are closed across Western Europe,  including London’s Heathrow, where up to 180,000 people fly in a typical day.

Iceland is a volcanic island, so this type of event is not unexpected. I included some spectacular photographs of explosions of Icelandic volcanoes in my Collins/Smithsonian book, VOLCANOES.

In 1963,  an area of the Atlantic Ocean near Iceland began to boil and churn. An undersea volcano was exploding and a new island was being formed. The island was named Surtsey, after the ancient Norse god of fire.