DATASTREME WES WEEK NINE: 28 March - 1 April 2005

• Tsunami program on NOVA -- The science television program NOVA will air the program "Wave that Shook the World" on Public Broadcasting System (PBS) stations on Tuesday, 29 March 2005. This program focuses upon the efforts by experts at reconstructing the 2004 Indian Ocean tsunami in an effort to prepare for future tsunamis. A website is available that has links to a variety of additional tsunami information, including a Teacher's Guide to the program. Since local broadcast times may vary, please consult your local television listings. [NOVA PBS]
• Welcome Colorado snowstorm turns deadly -- A late winter snowstorm at the end of last week that dropped nearly 20 inches of snow on southwest Colorado was responsible for at least two fatalities, with one death caused by an avalanche near Breckenridge and another due to a traffic accident. The snow was welcome as it helped build the snow pack in a region that has experienced 5 years of drought. [USA Today]
• Tsunami Awareness Week in Alaska -- The Governor of Alaska, along with NOAA, has proclaimed next week (27 March-2 April 2005) as Tsunami Awareness Week in Alaska. This start of this week coincides with the 41^st anniversary of the series of devastating tsunamis that struck southeastern Alaska following several earthquakes. [Governor's Office] As a part of Tsunami Awareness Week, the first statewide test of the tsunami warning communications system in Alaska. [NOAA News]
• Rapid deployment of water and sanitation teams were crucial--The International Red Cross recently claimed that the rapid deployment of international emergency response teams helped prevent the widespread outbreaks of disease in regions affected by the December 2004 Indian Ocean tsunami because they were able to provide clean potable water and sanitation facilities to the survivors. [ENN] Some of the inexpensive water recycling systems developed by NASA and its US contractors for use in space have also been deployed to aid tsunami victims. [ENN]
• Sale of spring water to bottler nixed -- A judge in northern California recently ruled that the planned sale of spring water from near the base of Mount Shasta could not be sold to a major national company that sells bottled water since appropriate environmental impact studies were not performed. [ENN]
• First phase of rainforest drying experiment completed--Scientists from Woods Hole Research Center, along with several other collaborating universities and agencies are analyzing the results of the first phase of an experiment where large "umbrellas" have prevented rain to fall on a portion of the Amazon rainforest in Brazil in an attempt to assess the response of the rainforest to drier conditions associated with global warming, El Niño episodes and forest clear cutting. [EurekAlert!]
• South American wetlands could suffer fate similar to Everglades -- Scientists with the United Nations University are warning that South America's giant Pantanal wetlands, the world's most bio-diverse ecosystems and the largest freshwater wetland, could be threatened by agricultural, industrial and urban development on its borders, resulting in a fate similar to that experienced by Florida's Everglades. The Pantanal wetlands extend across west central Brazil, eastern Bolivia and northeastern Paraguay. [EurekAlert!]
• Severe water shortages ahead for China -- Chinese officials have recently noted that the potable water shortages in China are expected to worsen considerably in the future because of increased pollution of aquifers and lakes, along with increased demands from urban development projects. [ENN]
• Philippine groundwater dips to critical level--An official in the Philippine government from Manila recently reported that groundwater reserves in the Manila metropolitan are have declined and reached a critical level, necessitating implementation of water conservation efforts. [US Water News Online]
• Can Western golf courses remain green? Golf course managers in Arizona are facing a perplexing problem of how to maintain green golf courses while the region continues to endure drought conditions. While use of water for the courses would appear as a low priority, green courses provide a significant source of income for the region. [US Water News Online]
• New partnerships formed for the next GOES -- NOAA officials announced a new strategy for the upcoming GOES-R mission that will involve a partnership with NASA. The next GOES (Geostationary Operational Environmental Satellite) will have improved instruments and technologies to monitor the planetary environment as part of the Global Earth Observing System of Systems. [NOAA News]
• Nature blamed by more tropical activity--Hurricane expert, Professor William Gray of Colorado State University, recently said that nature rather than humans was to blame for the increased hurricane activity that could last for several more decades. He attributes this increased activity to the global ocean conveyor belt circulation. [USA Today]
• Global and US Hazards/Climate Extremes-- A review and analysis of the global impacts of various weather-related events, including drought, floods, and storms during the current month. [NCDC]
• Global Water News Watch -- Other water news sources can be obtained through the SAHRA Project at the University of Arizona [SAHRA Project]
• Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Seiche

You probably remember as a child agitating the bath water so that it sloshed back and forth in the tub. (If you never did this as a child, there's still time.) You produced a seiche, a phenomenon first studied in Lake Geneva, Switzerland in the 1700s. A seiche (pronounced "say-sh") is a rhythmic oscillation of water in an enclosed basin (e.g., bathtub, lake, or reservoir) or a partially enclosed coastal inlet (e.g., bay, harbor, or estuary). With this oscillation, the water level rises at one end of a basin while simultaneously dropping at the other end. A seiche episode may last from a few minutes to a few days.

A seiche is a standing wave. Whereas wind-driven waves (pages 181-182 in your DataStreme WES textbook) are progressive in that they propagate through a body of water, standing waves are stationary. With progressive waves, crests and troughs travel along the wave surface but with standing waves, crests alternate vertically with troughs at fixed locations. For both progressive and standing waves, the restoring force is gravity.

With a typical seiche in an enclosed basin, the water level near the center does not change at all although that is where the water exhibits its greatest horizontal movement; this is the location of a node. At either end of an enclosed basin, vertical motion of the water surface is greatest (with minimal horizontal movement of water); these are locations of antinodes. The motion of the water surface during a seiche is somewhat like that of a seesaw: The balance point of the seesaw does not move up or down (analogous to a node) while people seated at either end of the seesaw move up and down (analogous to an antinode).

Go to the University of Delaware's Seiche Calculator at http://www.coastal.udel.edu/faculty/rad/seiche.html. Set the "Modal Number" to 1 and then press "Calculate" for a graphical simulation of a seiche in an enclosed basin.

Partially enclosed basins usually have a node located at the mouth (rather than near the center) and an antinode at the landward end. Go to the Seiche Calculator, set the "Modal Number" to 0.5 and then press "Calculate" for a simulation of a seiche in a basin open to the right. Furthermore, some basins are complex and have multiple nodes and antinodes; these can be simulated on the Seiche Calculator by selecting different values of "Modal Number" greater than one.

A seiche can be induced by wind, regional differences in air pressure, earthquakes, or tidal forces. For example, wind blowing persistently in the same direction down the long axis of a bay causes water to pile up at the downwind end of the bay. When the wind slackens, the water oscillates (as a seiche) back-and-forth from one end of the bay to the other until eventually the water calms to a horizontal surface. A line of thunderstorms moving eastward from Wisconsin in late May 1998 produced a seiche in Lake Michigan that killed several people by drowning at the southern end of the lake. Previous seiches have produced 8 to 10 ft waves on Lake Michigan. A tsunami generated a seiche in the harbor of Hilo, HI following a major earthquake in the Aleutian Islands on 1 April 1946.

The natural period of a seiche depends on the length and depth of the basin and generally ranges from minutes to hours: The period is directly proportional to basin length. For example, the natural period of a seiche in a small pond is considerably shorter than its period in a large coastal inlet. Also, for the same basin, the natural period is inversely proportional to water depth; that is, the period shortens as water deepens. Using the Seiche Calculator, you may wish to experiment with different values of basin length and depth. Conversely, one can estimate the average depth of a lake by determining the period of the seiche and the length of the lake.

Usually a seiche in a lake or harbor is of little concern because the changes in water level are minor--often only a few centimeters. Under certain circumstances, however, a seiche may grow to great heights with serious consequences including flooding and damage to moored vessels. A seiche grows as a consequence of resonance, that is, when the period of the disturbance (e.g., wind, earthquake) matches the natural oscillation period of a specific basin. Recall again your youthful bathtub experience. By timing your rhythmic disturbance of the water to match the natural period of the tub (about 1 second), you were able to cause the seiche to build until the water splashed out of the tub and onto the floor. Through resonance, vibrations from the 1994 Northridge, CA earthquake caused swimming pools to overflow throughout Southern California. In bays open to the ocean, if the period of tidal forcing matches the natural period of the bay, resonance can greatly increase the tidal range.

Concept of the Week: Questions

1. Seiches are [(standing) (progressive)] waves.
2. The natural period of a seiche [(depends on) (is independent of)] the size of an enclosed basin.

• 28 March 1902...McMinnville, TN (elevation 900 feet) received 11.00 inches of precipitation, setting a 24-hour precipitation record for the Volunteer State. (National Climate Data Center).
• 28 March 1964...A tsunami generated by an earthquake (which rated 9.2 on the Richter scale) in Prince William Sound, AK produced a major surge wave that was approximately 100 ft above low tide and caused major damage to Whittier (where 13 died) and other coastal communities in Alaska. The death toll from the earthquake and associated tsunami waves was at least 122, with 108 in Alaska. The earthquake and tsunami caused $311 million in property damage. The first wave took more than 5 hours to reach the Hawaiian Islands where a 10-foot wave was detected, while a wave that was 14.8 feet above high tide level traveled along portions of the West Coast, reaching northern California 4 hours after the earthquake. Nearly 10,000 people jammed beaches at San Francisco to view the possible tsunami, but no high-amplitude waves hit those beaches. (The University of Washington) (Accord's Weather Guide Calendar) (US Coast Guard Historians Office)
• 28 March 1980...Although springtime was starting in the Rocky Mountains, the snow just kept on coming! One foot or more of snow fell over portions of eastern Colorado, southwest Nebraska, northwest Kansas and southeastern Wyoming. Winds reached 40 mph and Valentine, NE received 13 in. of snow. North Platte, NE checked in with 15 in. (Intellicast)
• 28 March 1998...Three Boy Scout troop members died when their sport utility vehicle was swept away as they tried to cross a running wash just north of Sunflower, AZ. (Accord's Weather Guide Calendar)
• 29 March 1886...Atlanta, GA was drenched with a record 7.36 in. of rain in 24 hours. (The Weather Channel)
• 29 March 1920...Clear Spring, MD received 31 inches of snow in 24 hours to establish a state record. (Sandra and TI Richard Sanders - 1987)
• 29 March 1980...Heavy rains produced mudslides in Natchez, MS. The slides covered two buildings on Silver Street, killing 3 people and injuring 4. (Intellicast)
• 29 March 1989...Thunderstorms produced torrential rains in northeastern Texas and southwestern Arkansas. Longview, TX reported 14.16 in. of rain. More than 11 in. of rain at Henderson, TX caused a dam to give way, and people stranded in trees had to be rescued by boat. Total damage in northeastern Texas was estimated at $10 to 16 million. (The National Weather Summary) (Storm Data)
• 29-31 March 1848...An ice dam at the neck of Lake Erie and the entrance to the Niagara River between Fort Erie, ON and Buffalo, NY caused by wind, waves and lake currents stopped flow of water over Niagara Falls for 30 hours, commencing during the late hours of the 29^th. (Accord's Weather Guide Calendar) (The Weather Doctor)
• 31 March 2000...The water temperature of Lake Erie at Buffalo, NY was 39 degrees Fahrenheit on the last day of March, tying the maximum temperature for the date with that of 1998. Ice was present in 61 of 74 years on the 31^st, but this was third year in a row with open water. (Accord's Weather Guide Calendar)
• 1 April 1946...The Scotch Cap Lighthouse on Unimak Island in Alaska's Aleutian Islands was shaken by two earthquakes in a 27 minute span, then obliterated by a tsunami wave. The entire five-man crew was killed and the lighthouse antenna (105 ft above sea level) was washed away. Some debris was found 115 ft above sea level. The tsunami that propagated across the Pacific Ocean was responsible for more than 165 fatalities and over $26 million in damage. Many of the casualties were on the Hawaiian Islands, especially in Hilo on the Big Island. This tsunami was responsible for the development of the current Pacific Tsunami Warning System. (University of Washington) (Accord's Weather Guide Calendar) (US Coast Guard Historian's Office)
• 2 April 1958... One of the most destructive coastal storms in years battered New England (31 March-3 April). Some beaches between Portland, ME and Cape Cod, MA were eroded by approximately 50 ft. Miles of sea walls and bulkheads were either breached or demolished. Many beachfront cottages in Massachusetts, New Hampshire and Maine were sandblasted. (Accord's Weather Guide Calendar)
• 2 April 1997...An intense winter storm slammed the Maritime Provinces. Freezing rain knocked out power to more than 4,000 homes on Prince Edward Island. (The Weather Doctor)
• 3 April 1982...Wind-driven ice from Lake Winnebago in east central Wisconsin piled to 40-ft heights on the lake's eastern shoreline, damaging buildings in the Stockbridge area. Winds reached 80 mph across Wisconsin. (Accord's Weather Guide Calendar)

Return to DataStreme WES Homepage

URL: DSWES/news.html
Prepared by AMS WES Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2005, The American Meteorological Society.