DataStreme WES Week Eight: 25-29 October 2004

• Typhoon death toll continues to rise in Japan -- As of Sunday, officials in Japan report the deaths of at least 77 people as a result of the passage of Typhoon Tokage across western Japan last week. This typhoon (counterpart of a hurricane in the western North Pacific) was the deadliest tropical system in more than a decade. It produced torrential rains, strong winds and high waves. Most of the fatalities were the result of mudslides caused by the rain. [USA Today]
• Early season blizzard costly -- A storm system swept across the Sierras last week and was accompanied by heavy snow and strong winds that resulted in the deaths of two climbers who were stranded in Yosemite National Park, while 14 stranded hikers in Sequoia National Park were eventually rescued. [USA Today] This storm had produced heavy rain and mountain snow across southern California and Nevada, resulting in flash flooding and mudslides. [USA Today]
• Better agricultural practices could ease world water supply problems -- Ecologists at Cornell University recently reported that if some of the strain on the world's water supply would be eased it US farmers would exercise some water conservation practices. [Cornell University]
• Control of Great Lakes water diversion urged -- A planning committee in Ashland, a city in northern Wisconsin along the shores of Lake Superior, has urged officials in Wisconsin and the other seven states bordering the Great Lakes to implement a water compact that would protect the water resources of the Lakes by placing tighter controls on the diversion of lake water to other locations outside the basin. [US Water News]
• Many drinking water utilities have lead contamination -- The Washington Post has conducted an investigation that reveals that as many as 65 of 3000 water utilities have not revealed that their drinking water has levels of lead that are considered unsafe and are above the EPA mandated levels. [US Water News]
• Australian city plans to safeguard its water supply -- Sydney, Australia has announced plans to spend hundreds of millions of dollars to maintain its water supply over the next decade. The neighboring eastern Australia has been experiencing a two-year drought, resulting in low levels for the city's reservoirs. [ENN]
• 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: Chesapeake Bay Ecosystem

Chesapeake Bay is the nation's largest estuarine ecosystem; it is more than 300 km (185 mi) long, 65 km (40 mi) at its broadest, and averages about 20 m (66 ft) deep. The estuary was formed by the post-glacial rise in sea level that flooded the valley of the ancient Susquehanna River. The Bay receives about half its water from the Atlantic Ocean and the other half from the more than 150 rivers and streams draining a 166,000 square kilometer land area encompassing parts of New York, Pennsylvania, West Virginia, Delaware, Maryland, Virginia, and the District of Columbia. Major rivers emptying into Chesapeake Bay include the Potomac, Susquehanna, York, and James.

An estuary is a complex and highly productive ecosystem formed where seawater and fresh runoff meet. In Chesapeake Bay, more-dense seawater creeps northward along the bottom of the estuary, moving under the less-dense fresh water flowing in the opposite direction. This circulation combined with wind-driven water motions causes salinity to decrease upstream in the Bay, from values typical of seawater at its mouth to freshwater values at its northern margin.

As in all ecosystems, organisms living in estuaries depend on one another and their physical environment for food energy and habitat. This interdependency is evident in food chains, pathways along which energy flows and materials cycle. Phytoplankton and submerged aquatic vegetation (e.g., marsh grass) are the primary producers in estuarine food webs. (Producers acquire energy from solar radiation through photosynthesis and are at the bottom of food chains.) Consumers in food webs are organisms that derive their energy by eating producers or other consumers. Chesapeake Bay consumers include zooplankton, finfish, shellfish, birds, and humans. Through cellular respiration, producers and consumers convert energy to a form that the organism can use for growth and reproduction.

Human activity has greatly modified Chesapeake Bay with consequences for the functioning of its ecosystem. Much of the original forests that covered its drainage basin were converted to farmland, roads, cities, and suburban developments. These modifications accelerated the influx of nutrients (i.e., compounds of phosphorous and nitrogen), sediment, pesticides, and other pollutants. More nutrients spur growth of algal populations and when these organisms die (in mid-summer), their remains sink to the bottom. Decomposition of their remains reduces dissolved oxygen levels in the Chesapeake's bottom water. More sediment makes the water cloudy, reducing sunlight penetration for photosynthesis.

One casualty of human modification of the Chesapeake Bay ecosystem was marsh grass--reduced by 90% from historical levels. Marsh grass anchors sediment and dampens wave action thereby controlling erosion and turbidity. Marsh grass is a food source for many organisms including waterfowl and small mammals and serves as a primary nursery ground for crabs and many species of fish. Reduction of this habitat along with over-fishing has been implicated in the decline of populations of blue crabs, a mainstay of the Bay fishery for more than a century. Over the past decade, the number of adult female crabs has plunged by 80%. Without adequate protection by marsh grass, the blue crab is more vulnerable to predation by striped bass (i.e., rockfish). Striped bass turned to blue crabs as a food source when fishing reduced the numbers of menhaden, their preferred food. Menhaden is a marine fish in the herring family and the Bay's top fishery by weight.

Concept of the Week: Questions

1. Within the waters of Chesapeake Bay, salinity [(is relatively uniform)(varies greatly)].
2. Marsh grass is a [(producer)(consumer)] in the Chesapeake Bay ecosystem.

• 25 October 1859...The Royal Charter Storm, named after the loss of the fully rigged ship Royal Charter off the coast of Anglesey, England, drowned about 500 people, along with the loss of gold bullion. The ship was one of over 200 vessels wrecked between 21 October and 2 November, with the loss of around 800 lives, and led to the introduction of gale warnings in June 1860. (The Weather Doctor)
• 25-26 October 1980...The combination of unusually high tides and southeasterly winds gusting to 75 mph generated waves with heights to 25 ft, resulting in serious flooding, beach erosion and sea wall damage along the Maine coast. Wind damage was considerable and as many as 100,000 homes were without power for up to 40 hrs. (Accord Weather Calendar)
• 26 October 1998...Hurricane Mitch, a category 5 hurricane (on the Saffir-Simpson Scale) for 33 hours, finally dissipated after becoming the strongest October hurricane on record in the Atlantic Basin. Estimated rainfall totals of up to 75 inches caused devastating flooding and mudslides in Honduras and Nicaragua for days. Estimated death toll from this hurricane was more than 11,000, the greatest loss of life from a tropical cyclone since 1780. (Accord Weather Calendar)
• 28 October 1982...A severe thunderstorm produced softball-sized hail and nearly 4 hrs of flooding rains at Al-Khafqi, Saudi Arabia. Eleven people were killed, along with the destruction of vehicles and buildings. (The Weather Doctor)
• 28 October 1991...Typhoon Thelma devastated the Philippines. Reports indicated that 6,000 people died by catastrophic events related to the storm including dam failure, landslides, and extensive flash flooding. The greatest number of casualties occurred on Leyte Island where an 8-ft storm surge struck Ormoc, accounting for over 3,000 fatalities. (The Weather Doctor)
• 29 October 1999...Tropical Cyclone 5B, with sustained winds of 155 mph, made landfall at Paradwip (Orissa, India). A storm surge of at least 20-ft height swept at least 12 mi inland. More than 10,000 people were killed. With 2 million homes either damaged or destroyed, 35 million people were left homeless. Damage from this tropical cyclone was $1.5 billion. (Accord Weather Calendar)
• 30 October-1 November 1991...After absorbing Hurricane Grace on the 29^th, an intense ocean storm took an unusual course and moved westward along 40 degrees north latitude and battered eastern New England with high winds and tides. Winds had already been gusting over 50 mph along the coast 2 days before, so seas and tides were very high. Major coastal flooding and beach erosion occurred all along the New England, New York, and New Jersey coastlines. Over 1000 homes were damaged or destroyed with tides 4 to 7 ft above normal. Wind gusts reached 78 mph at Chatham, MA and 74 mph at Gloucester, MA. One ship east of New England reported a 63-ft wave. Total damage from the storm was $200 million. On 1 November this ocean storm underwent a remarkable transformation. Convection developed and rapidly wound around the storm center and an eye became visible on satellite imagery. Air Force reconnaissance aircraft found a small but intense circulation with maximum winds of 75 mph. This evolution from a large extratropical low to a small hurricane is rare but not unprecedented. (Intellicast)
• 31 October 1876... A 10 to 50 ft storm surge ahead of the Backergunge cyclone flooded the eastern Ganges Delta in India (now Bangladesh). Over 100,000 drowned. (The Weather Doctor)
• 31 October 1846...Eighty-seven pioneers were trapped by early snows in the Sierra Nevada Mountains that piled five feet deep, with 30 to 40 ft drifts. Just 47 persons survived the "Donner Pass Tragedy". (The Weather Channel)
• 31 October 1874...A waterspout (a tornado-like vortex that travels over water) formed over Lake Erie and reached the lakeshore approximately 0.5 mi west of Buffalo, MY. Upon reaching the shore, it dissipated, scattering sand in all directions. (Accord Weather Calendar)
• 31 October 1965...Fort Lauderdale, FL was deluged with 13.81 inches of rain inches over a two day period (30^th-31^st), the second heavy rains in two weeks. This brought their rainfall total for the month of October to an all-time record of 42.43 inches. More road and street damage occurred and some homes were flooded for the second time. (David Ludlum) (The Weather Channel) (Intellicast)
• 31 October 1984...An exceptional thunderstorm at Al Wajh on the Red Sea coast of northern Saudi Arabia produced 4.81 inches of rain, which was more than the total rainfall there in the previous ten years. At Tabuk 150 miles to the north, 0.49 inches of rain fell to set a daily October rainfall record at that location. (Accord Weather Calendar)
• 1-6 November 1570... The All Saints Day Floods killed an estimated 400,000 people in Western Europe. (The Weather Doctor)
• 1 November 1861...A hurricane near Cape Hatteras, NC battered a Union fleet of ships attacking Carolina ports, and produced high tides and high winds in New York State and New England. (David Ludlum)

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Prepared by AMS WES Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2004, The American Meteorological Society.