Discovery News: Earth Impacts News

Des Moines: Before & After

Don't you love those before and after pictures? Unlike those funny skin cream ads in my wife's magazines, the Earth doesn't glower in the first image and grin serenely in the second. Here is a set from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite. The "before" on the far left is Des Moines, Iowa, in June 2005 -- a typical June view of the city, river and environs. The "After" is June 29, 2008, after the floods struck the city (both images are clickable for much larger versions). By the time the satellite passed over the city the urban flooding had subsided, but downstream to the southeast of the city, the flooding was still pretty awful.

These images are false color, incidentally, showing visible and infrared light. This sort of view makes it easier to see standing water, which comes out as dark blue. Trees and other plants are bright red, buildings and roads are silver-gray and clouds are white. More images of this flood are available here.

The NASA images were created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

Streaky Weather

My stepfather Roy wrote to me today with a great meteorological question:

Hi Larry- Looking for the name of rainfall that does not strike the ground, but evaporates in mid-air. Tried dictionary, thesaurus, and all  etc., etc. Help! I'm going nuts!

I know exactly what he's talking about, but can't remember the word either. It's just one of those words you hear and think, "That's a neat word. I'm going to remember that," and promptly forget it. All that's left is this irritating space on your tongue where you know a word should be. Fortunately, the Internet doesn't have that problem (rather, has a surplus of words where they should and shouldn't be). A quick and discriminating look around and I found the word we wanted. It's virga. No, not Virgo, so all you astrologers can just calm down. Virga is from the Latin word for "streak" (not the 70's era verb, btw, so all you naturists can calm down too). Now let's try to remember it!
Image copyright University Corporation for Atmospheric Research    

California Smokers

Here's a powerful image from NASA showing the smoke from California wildfires. It's so murky that I find it hard to find the San Francisco Bay area, which is usually a great landmark when looking at satellite imagery of the California coast. Click on the image to see the full-scale version.

The smokiest part of the state appears to be the Sacramento Valley. The Big Sur blaze that's getting a lot of ink is further south, just below the big knob of bright white fog that is filling the Monterey Bay (about two-thirds down the image). Smoke is gray, fog and clouds are bright white.

This June 25 image is in natural-colors and from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite.

Soft & Hard Weather

CAHERSIVEEN, IRELAND -- Soft weather. That's what my Irish cousins call the drueling rain and gray ceilings of many days here in Ireland, particularly in Ireland's southwest. We found ourselves -- my wife, sons and I -- in rather soft weather in downtown Dublin a few days ago, and now again on the Ring of Kerry. I've never really understood how the term soft applied to weather. It sure fits, but I'm not sure why or how. Is it the way the rain softens the ground to mush? Or maybe how the edges of the sky blur into the hillsides, making as soft a horizon as can be imagined? Perhaps a look at the word's opposite wold be instructuve. What's hard weather? In my mind that's maybe sleet or blizzards or intense heat. The hardest weather I've ever experienced is perhaps as a ranger in Death Valley. Stepping out of a building the sun and heat struck my head like a hammer on a bell. It hurt. Never called it hard weather in those days, though. It was just normal summer 120+F heat. I remember how I used to post the daily weather forecasts on a board in Death Valley's Furnace Creek visitor center. The official text invariably read "Sunny and warm...." On one 122-degree July day I had finally had enough of the official forecast. Thereafter I always posted it as "Blazing hot." Given the chance again I'd even venture to write "Hard weather."

Myanmar: Before & After

Here are two satellite images from NASA's Earth Observatory showing the flooding in Myanmar from Cyclone Nargis. Click on them to enlarge. Here's some of NASA's explanation:

"Flood water can be difficult to see in photo-like satellite images, particularly when the water is muddy. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite use a combination of visible and infrared light to make floodwaters obvious. Water is blue or nearly black, vegetation is bright green, bare ground is tan, and clouds are white or light blue."

Urban Tornadoes -- *#@! Happens

This morning when I went online to check my email I was surprised to discover that Atlanta had been hit by a tornado. Even more surprised were my Atlanta-area-resident in-laws, who are visiting us here in New Mexico. Besides concern for their friends and property, I experienced another feeling: deja vu. It was just a little over a year ago that I wrote about this possibility in a news story for Discovery News. Here's the link

Two lessons that can be gleaned from this current extreme weather incident: 1) Atlanta was not the worst-case scenario of an urban tornado and 2) Atlanta's night of trouble will be the focus of some intense scientific analysis in coming months. You can count on it that I'll be reporting on the results of those studies.

God & Tornadoes

The other day I walked by the TV as my wife was watching the news and saw the national weather map. There was a diagonal curve sweeping across the Southeast U.S., with temperatures in the 30s north of the line and 70s to the south. A little alarm went off in my head. "That's not good," I thought, then forgot about it.
It came back to me later that night when I checked the news online and saw the initial death counts. It was a horrific night for hundreds of thousands of people. And I wondered: How long would it be before someone claimed it was divine punishment? Not long. Just Google "tornadoes divine punishment" for a small taste. There are all sorts of crazy ideas out there, and even a lot of political screaming in the comments sections of news stories. As if the disaster itself were not bad enough.

The truth, of course, is that tornadoes happen. Mother nature doesn't give a whoop-dee-doodle whether there are people in the way. And while we may be pushing the climate and that climate drives the weather, neither humans or our deities are manning the controls of this tiny blue planet. At best, we are just egging on a bull in a china shop, without a clue what the beast will do -- besides the regular bullish stuff. Pretty darned stupid way to live on a planet.

Tornadoes & Global Warming: Yes or No?

Did global warming cause the horrific and unseasonable tornadoes that struck the Midwest U.S.A. this week? The question might be inevitable, but the answer isn't. The way climate and weather experts have explained it to me, there is no simple way to directly physically link any lone weather event to global warming. It's sort of like asking a physician which individual cigarette caused one particular lung cancer cell (okay, it's not a perfect analogy, but it's late and I'm tired). Instead, they prefer to say that global warming will increase the frequency of extreme weather events -- like the tornadoes.

Now you might be thinking "Those darned scientists are just trying to avoid giving us a straight answer." After all, we would really like to know if these tornadoes, heat waves, floods and hurricanes are really being flung at us by Exxon and Hummer drivers. Luckily, if asked just that way -- as a pile of ugly consequences from haphazardly pumping millions of years worth of naturally sequestered carbon into the atmosphere over less than two centuries -- the answer is a little easier. The answer (off the record, okay?) is very probably yes.

 

Stuff that flows downhill

The terrible flood in Fernley, Nev., sure takes me back: All the way back to 1996 when the same darned thing happened to Fernley. There were far fewer homes affected that time, partly because far fewer people lived in Fernley. I bring this up because I was there in '96 as a reporter at the Lahontan Valley News, a daily newspaper across the county line in Fallon, Nevada. So I have some questions about what happened this time around.

The canal which failed, just for a little background, carries water from the Derby Diversion Dam -- shown in this Bureau of Reclamation photo -- on the Truckee River to help irrigate farms way the heck over in Fallon. For about a century there wasn't much to worry about near that canal. Not many homes to flood. A lot of scrubby vegetation at risk, nothing more.

I wonder what the developers of the vast tracts of new homes directly downhill from this century-old canal have told their home buyers since 1996? I wonder if they mentioned the 1996 breach at all? And if they did, how did they explain away to the buyers, county planners and mortgage lenders and insurance companies the fact that water runs downhill? Man, that's a sales pitch I'd really like to hear! If I was one of those homeowners in Fernley, I think I'd be explaining to the developers right now that water is not the only thing that flows downhill. This disaster was no Act of God but 100 percent Act of Man. Some Nevada lawyers must be already donning bibs to catch the saliva.

If it’s yellow let it mellow. If it’s brown…

If you could correctly finish the above sentence 30 years ago, there’s a good chance you grew up the
Western U.S. Last week I was reminded of the old water-conserving phrase when my visiting mother-in-law mentioned it as a rather new and unsavory concept that Georgia state officials were foisting on her and others living in the greater Atlanta area. As you may have heard, Georgia is experiencing a historic drought. People there and in other parts of the Southeast are being told to rapidly change decades of habits in order to conserve the dwindling water supply. It’s a lot to ask, but droughts are nothing to fool with. In a Discovery Channel online interactive a few years ago I compared droughts to a slow-killing disease like some cancers or tuberculosis. Droughts can be every bit as deadly as a hurricane or earthquake –- even more so sometimes -- but they are tortuously drawn-out. 

For all this, droughts are surprisingly tricky to define. Last time I checked, there were at least a dozen definitions of drought. It all depends on where you live and what you are doing with water. Where I was raised it was normal to see not a drop of rain from April to November. The same conditions would be a pretty worrisome drought in Maryland. There are drought definitions based on soil moisture measurements, others on economic impacts, and still others on the numbers of days without precipitation. You name it, if there’s a water-related impact, there’s probably a drought definition for it. This makes it all the more amazing that anyone can say anything on a nationwide or global scale about droughts. So check out the U.S. Drought Monitor page and prepare to be impressed. Oh, and in case you are blessed to live in a place where water supply is never a problem, the rest of the phrase, is "...flush it down."