Tornadoes — Storms of Mystery

An outbreak of 69 confirmed tornadoes during the last four days of April, 2014, took 35 lives and caused over $1 billion in property damage. Two Arkansas towns north of Little Rock – Vilonia and Mayflower — were the hardest hit. The rash of tornadoes also devastated communities in Oklahoma, Kansas, and Texas.

Tornadoes kill an average of 60 people a year in the US, according to NOAA. This varies greatly by year. 2011 was one of the most destructive and deadly on record. An F4 tornado with wind speeds of 200 mph (322kp/h) wiped out Joplin, Missouri, killing 162. Earlier that year, an F-4 struck Tuscaloosa, Alabama, killing 65 and leveling a wide path through part of the city. Total fatalities for all tornadoes that year were 551, with damages estimated at $28 billion.

Tornadoes are a product of high-energy cloud formations called supercells. In the spring, when warm, moist air flows into the Midwest and Southeast from the Gulf of Mexico, it rises and mingles with layers of cooler, drier air coming in from Canada and the mountain west. The warm air condenses when it meets the cool air, forming cumulus clouds. Rising convection currents create energy and instability inside the cumulus formation. When the energy level peaks high enough, a rotating updraft or mesocyclone develops and the storm formation becomes a supercell. In some cases, the energy moves vertically down from the base of the supercell to the ground in the form of a spinning vortex.

There are several mysteries about tornadoes. Scientists know generally how they form and what happens once they do, but do not know why some storm clouds morph into supercells and most do not. Also, once a cumulus buildup turns into a supercell, why do 30% produce tornadoes, and 70% only rain or hail?  Even though the National Weather Service has gotten quite good at forecasting tornadoes in a specific area, the behavior of a tornado once it touches down is not always predictable.  Tornado paths range in width from 100 yards (91m) to 2.6 mi (4.3km), and the length from 10 miles (16km) to hundreds of miles. They can last from a few seconds to more than an hour. They move across the land in a northeasterly direction at between 30 mph and 70mph (48 to 112kp/h).

Not all states in “Tornado Alley” have building codes that require storm shelters in schools and hospitals, where many of the casualties have occurred in past tornadoes. If more states included that in their building codes, it would undoubtedly save lives in the future.

 

 

 

Are Volcanoes Slowing Global Warming?

In 2013, the world pumped 36 billion metric tons (40 billion US tons) of CO2 into the atmosphere through the burning of fossil fuels. Such emissions form a carbon dioxide blanket that allows the sun to penetrate, but prevents much of the surface heat from reflecting back into space. As a result, the oceans are rapidly warming, arctic sea ice is diminishing, and glaciers and the Greenland Ice Sheet are melting at a record rate.

The world’s surface temperature has steadily increased for the past 150 years, and it was assumed the curve would keep climbing at the same rate. But unexpectedly, global surface temperature peaked to its highest historical level in 1998, then flattened out and has remained about the same since, raising questions in the scientific community.

A Lawrence Livermore National Laboratories study that appeared in the Feb. 23, 2014, issue of the journal Nature Geoscience suggests one reason for this unexpected development is the higher than normal rate of volcanic activity over the past 15 years.  Eruptions during that period included 17 ranked VEI 4 on the Volcanic Explosivity Index. A VEI 4 is termed cataclysmic and sends an ash plume 10 to 25km (6 to 15 mi) into the air, sufficient to penetrate the stratosphere with sulfur dioxide aerosols that remain there for months, even years.

“In the last decade the amount of volcanic aerosol in the stratosphere has increased, so more sunlight is being reflected back into space,” said Lawrence Livermore Climate Scientist Benjamin Santer, lead author on the study. “This has created a natural cooling of the planet and has partly offset the increase in surface and atmospheric temperatures due to human influence.” The paper states the research team found evidence for significant correlations between volcanic aerosol observations and satellite-based estimates of lower temperatures, as well as sunlight reflected back into space by the aerosol particles.

Santer’s conclusions seem to be supported by an earlier study by the University of Saskatchewan. In this study, the researchers found that sulfur dioxide aerosols from a very small African eruption had “hitchhiked” their way into the stratosphere. Warm air rising from the seasonal Asian Monsoon lifted the volcano’s aerosols from the lower atmosphere into the stratosphere, where it was detected by the Canadian Space Agency’s satellite OSIRIS, an instrument specifically designed to measure atmospheric aerosols. Even though coming from a small eruption, the concentration of particles was the largest load of SO2 aerosol ever recorded by OSIRIS in its 10 years of operation.

The Lawrence Livermore paper suggests that one other possible contributor to the temporary cooling effect is the unusually long and low minimum in the solar cycle. Don’t be surprised to see surface temperatures start climbing again when volcanic activity subsides and the cooler phase of the solar cycle concludes.

 

 

 

 

 

Why Chile Has So Many Earthquakes & Tsunamis

The Magnitude 8.2 quake that struck off the coast of Chile on April 1, 2014, was the latest in a series of major earthquakes and tsunamis to hit that area in recent years. The undersea quake and resulting 7 ft. (2.1m) tsunami killed 7, toppled buildings, and severely damaged the Chilean fishing fleet.  Earthquake/tsunami events in 2010 (M8.8), 2007 (M7.7), 2005 (M7.8), and 2001 (M8.4) killed more than 1,000 and inflicted billions of dollars in property damage .

The most powerful earthquake ever recorded, a Magnitude 9.5, hit the coast of Chile on May 22, 1960. The monster quake triggered an 82 ft (25m) tsunami that not only battered the west coast of South America, but rolled across the Pacific Basin, devastating Hilo, Hawaii, and damaging coastal villages as far away as Japan and the Philippines. Some sources estimate 6,000 dead and $800 million in property loss (6 billion in 2014 dollars).

Why does this area of planet earth spawn so many high-magnitude earthquakes and punishing tsunamis?

One explanation is that the collision of the two tectonic plates that meet off the South American west coast occurs, in geologic terms, at a very high rate of speed. The oceanic Nazca Plate and the continental South American Plate converge in the Peru-Chile trench that lies about 100 mi (160km) off the coast. The overriding South American Plate moves eastward at 10cm a year, while the subducting Nazca Plate pushes west at 16cm/y, a closing velocity of 26cm/y (about 10 in.), one of the fastest absolute motions of any tectonic plate. The Africa Plate, for example, moves approximately 7 times slower.

This high closing velocity builds up fault line strain much faster than it does when slower-moving plates converge. Every few years, tension on the Peru-Chile fault line builds up to a breaking point. In this latest earthquake on April 1, a 100 mi. (160km) section of the fault line ruptured, allowing the Nazca Plate to ram under the South American Plate. This sudden violent action 12.5 mi (20.1km) below the ocean floor triggered the tsunami and the 8.2 earthquake, and at the same time wedged the South American Plate higher. Uplifting from frequent fault line failures continues to build the Andes Mountain Range into one of the highest in the world. During the 1960 M9.5 quake, some coastal areas uplifted as much as 10 ft. (3m).

As long as the two tectonic plates that meet off the South American coast move geologically at such high speed, major earthquakes and tsunamis will keep happening. We hope the zoning laws and building codes put in place by the governments of Chile and Peru will keep the damage and loss of life to a minimum.  

Why Did the Hill Come Down?

As of this writing, 21 people have been confirmed dead and 30 are missing in the disastrous March 22, 2014, Oso, Washington mudslide. We send our condolences to all those affected by this terrible tragedy.

At the same time, we have to ask ourselves why a forest-covered mountainside would suddenly shear off and bury an entire community of 30 homes under a 1 square mile (2.6km²) mud and debris slide 40 ft (12m) deep.

Two main reasons have been given. One is that the hill had become saturated after weeks of heavy rainfall. The rainfall in that area during the month of March was 200% of normal. Although the soil there is compacted clay that tends to be impermeable, it is believed there were cracks at the top that allowed the rain to penetrate. The other reason for the failure is that the swollen Stillaguamish River at the base was undercutting the toe of the hill. With the base of the hill weakened and the slope heavy with soaked-in rain, the hill collapsed.

After a number of landslides had been reported in that area during the prior 40 years, the US Army Corps of Engineers did a survey there in 1999 and issued a report warning of “the potential for catastrophic failure.” In 2006, a section of that same hill collapsed and blocked the course of the river. Other state and local agencies had examined the hill at various times and all concluded it was unstable. Whether the permit-issuing authorities were aware of those findings is not known. What is known is that building permits for that location continued to be issued, even after the 2006 slide.

The last compilation of world landslide statistics was posted by the American Geographical Union for the year 2010. In that year, 6,211 people died in 494 landslide events worldwide. 83,275 landslide deaths were reported for the period September, 2002 to December 2010, an average of a little more than 10,000 a year. People living in the mountains of China, India, Central America, the Philippines, Taiwan, and Brazil were the most vulnerable during that period. Landslides and mudslides often occur when intense rainfall from tropical storms and monsoons saturate hillsides that have been compromised by logging, farming, and construction. Although not as highly dramatic as earthquakes and tsunamis, landslides may be the most costly of all natural disasters in loss of life and property.

In the United States, landslide fatalities average between 25 and 50 a year, according to the Centers for Disease Control and Prevention. Using airborne Lidar, a laser-based mapping system, it is now possible to set up a national data bank on areas throughout the US that are susceptible to hillside failure, but it would be a long and very costly project. Until such a survey is done, local jurisdictions will have to rely on other methods to determine landslide-prone areas. Even knowing the possible dangers, people will still build homes below unstable hillsides, in fire areas, and flood plains. It is up to local zoning authorities to prohibit building in these hazardous places.

 

 

Offshore Wind Farms

Constant winds in coastal waters make offshore wind farms highly productive. Most offshore wind turbines are installed on pilings in shallow waters within a few miles of the shoreline, but there are some on floating platforms farther offshore.

The United Kingdom’s 20 offshore wind farms supplied 10% of that nation’s total electrical power production in January, 2014, and 11% in February. Britain is the world leader in number of wind farms located in coastal waters, and in total amount of energy produced. Germany, Netherlands, Denmark, Belgium, and Sweden are close behind with another 58 offshore wind farms, and dozens more under construction or in the planning stage. Offshore wind farms are projected to produce 4% of total European power by 2020, and 15% by 2030.

The US leads the world in amount of energy produced by wind turbines: 120 billion kilowatt hours in 2013, representing more than 4% of US energy production. However, all US wind farms are currently land based. At this time, the US has no offshore wind farms. Plans are on the drawing board and permits have been granted for offshore wind farms in Massachusetts, New Jersey, Rhode Island, and Oregon, but so far no construction work has started. Reasons given are reluctance to increase the cost to the rate payer, and NIMBY (not in my backyard) campaigns by homeowners and environmental groups.

The US Atlantic and Gulf coasts provide more suitable sites for offshore installations than the Pacific Coast, because of a longer and shallower slope out to the edge of the continental shelf. In some areas, shallow waters extend out as far as 200km (160 mi) on the Atlantic coast. The continental shelf drop-off to deep water on the Pacific coast is steeper and more abrupt and not as suitable for shallow water farms. A Seattle company has obtained a lease from Dept. of Interior for 15 square miles of federal waters off Coos Bay, Oregon, for a wind farm on floating platforms anchored by cable to the ocean floor.

Could a massive offshore wind farm project also serve as a buffer against hurricanes and storm surges? Yes, according to a study by Mark Jacobson, professor of civil and environmental engineering at Stanford, and two co-authors, published in the journal Nature Climate Change. In the study, the researchers used computer simulations of Hurricanes Katrina, Sandy, and Isaac to determine the effect of massive offshore wind farms on wind speed and storm surge. In the case of Katrina, the researchers found that an array of 78,000 turbines in coastal waters would have reduced wind speed at landfall 65% to 78%, and storm surge by 79%. Similar results were obtained for Sandy and Isaac. It is not likely that 78,000 turbines will ever be installed offshore in one farm, but if that had been the case, and if the researchers’ conclusions are correct, it would have brought Katrina’s wind speed down to 28 to 44 mph from 125 mph, saved thousands of lives, and $100 billion in Gulf Coast reconstruction. Also, that many turbines would be producing millions of megawatts of clean power. It’s something to think about.  

 

 

 

 

 

 

Sun, Wind, & Fresh Water

Converting ocean water into fresh water is energy intensive, and therefore expensive. Saudi Arabia is a desert kingdom with plenty of oil but very little fresh water. The Saudis burn 1 million barrels of oil a day to produce 60% (4 billion cubic meters) of its total fresh water supply through desalination. If exported onto the world market, those 1 million barrels of oil would bring Saudi Arabia $115 million a day, but it is worth it to them to forgo the profits and have the fresh water. From an environmental standpoint, burning 1 million barrels of oil a day sends close to a half million tons of CO2 emissions into the atmosphere every day, contributing greatly to the pace of global warming.

To deal with these problems, the Saudis have joined with IBM to build a series of solar-powered desalination plants that could by mid-century produce a large share of the kingdom’s water needs.

However, the largest solar-powered desalination plant yet designed will be built in the United Arab Emirates. The Ras Al Khaimah plant, scheduled to start production in 2015, will produce 100,000 cubic meters (approx. 22 million gallons) of fresh water a day, and in addition, provide 20 megawatts of electrical power daily. The developers estimate they will be able to deliver water at a cost of $0.75 per cubic meter. Average cost per cubic meter of water delivered to households in the United States runs between 0.35 and 0.40. Most of the desalination plants run by solar energy are situated in the Middle East where there is an abundance of year round sun and a scarcity of water.

The largest desalination plant run by wind power is near Perth in Western Australia. The Kwinana Desalination Plant produces 144,000 cubic meters of water a day (approx. 38 million gallons), about 17% of Perth’s water supply. The Kwinana plant is powered by the 80 Megawatt Emu Downs wind farm located 200 miles away. Because electrical power has to be supplied evenly 24/7, and because the wind stops blowing from time to time, the power from the wind farm goes into the grid on a trade-off basis. The wind farm contributes 270 Gigawatt hours a year into the power grid, more than offsetting the 180 Gigawatt/h year required to operate the desalination plant. There are a number of smaller desalination plants run by wind-generated electrical power that goes directly from the wind farm to the plant, but Perth has opted for the offset arrangement.

Most desalination plants are still operated with grid power generated by coal, oil, or natural gas because it is less expensive than spending hundreds of millions to construct solar arrays or wind farms. For example, Australia’s other desalination plants providing fresh water to Sydney, Melbourne, Adelaide, and other coastal areas use fossil fuel power from the grid. But more and more, new desalination plants around the world are being planned to operate on alternative power. At some point in the future, all our electricity will have to come from those sources.