WEEKLY WATER NEWS

DataStreme WES Week Five: 1-5 October 2007

Water in the News

(Thurs.) Lake infested by weeds -- Images made seven years apart by NASA’s Landsat 7 satellite shows the amount of the lake surface of Caddo Lake along the Texas-Louisiana state line that became covered with a floating aquatic weed. [NASA Earth Observatory]
(Thurs.) Tropical caves provide paleoclimate proxy records -- Scientists at Georgia Tech have found that the stalagmites retrieved from caves on the island of Borneo help provide a 25,000-year paleoclimatic record of an equatorial rainforest which they claim shows the important role of the equatorial Pacific in influencing large-scale climate change. The researchers have compared these records with polar ice core records. [EurekAlert!]
(Thurs.) Ocean iron fertilization project studied -- An international symposium held last week at the Woods Hole Oceanographic Institution had scientists, policymakers and industrial leaders discuss the issues and potential implications involved with the proposed fertilization of the ocean with iron as an intentional means for slowing rises of global temperature. [Woods Hole Oceanographic Institution]
(Tues.) Cloud seeding remains alluring -- Artificial weather modification designed to stimulate precipitation by seeding of clouds continues to lure farmers and others in drought stricken areas of the West and in other areas of the world. [USA Today]
(Tues.) Rainfall across equatorial Africa -- An image of the precipitation anomaly (difference between observed and average totals) obtained from data collected by NASA's Tropical Rainfall Measuring Mission (TRMM) satellite for a four-week span commencing in late August 2007 shows the above average precipitation totals across the Sahel and equatorial Africa. [NASA Earth Observatory]
(Tues.) Rivers slow to recover from acid rain -- Researchers at the United Kingdom's Cardiff University report that the water quality and aquatic life along the streams and rivers across Wales have been slow to recover from the adverse effects associated with acid rain over the last 20 years. [EurekAlert!]
(Tues.) Major dam project proposed in California -- California's Governor Arnold Schwarzenegger has submitted a $9 billion water bond plan to the state legislature that would include more than half the money earmarked for the construction of dams in the Golden State. [US Water News Online] Researchers at Duke University and NOAA’s Southwest Fisheries Science Center have concluded that additional dams that would be constructed along the rivers of California's Central Valley for water storage could harm Chinook salmon and other fish that swim upstream along these rivers to spawn. [EurekAlert!]
(Tues.) Environment preceding "Great Oxidation Event" is studied -- Scientists at the University of Maryland and Arizona State University who analyzed 2.5 billion-year old rocks collected from West Australia conclude that significant changes in the oxidation state of the environment occurred within both the earth's ocean and atmosphere within 40 million years prior to the "Great Oxidation Event" when microbial life arose at the end of the Archean Eon (~3.9 - 2.5 billion years ago). [EurekAlert!] University of Alberta scientists have dated this "Great Oxidation Event" at between 2.3 to 2.4 billion years ago. [EurekAlert!]
Eye on the tropics ---
- The eastern North Atlantic basin remained active. A tropical depression formed early last week over the central tropical Atlantic and intensified to become Tropical Storm Karen, the eleventh named tropical cyclone of the hurricane season as it moved to the west-northwest. By Saturday, it had dissipated east of the Leeward Islands. An image made by NOAA's GOES-12 satellite shows the clouds surrounding Tropical Storm Karen on Friday. [NOAA OSEI]
  Tropical Storm Lorenzo formed over the southwestern Gulf of Mexico early last week and intensified to become the fourth hurricane of the season before making landfall along the Gulf coast of southeastern Mexico early Friday. The torrential rain from former Hurricane Lorenzo produced flooding rain and mudslides that killed five people in eastern Mexico. [USA Today] An image obtained from data collected by the instruments on NASA's Tropical Rainfall Measuring Mission (TRMM) satellite shows the large rainfall rate in the eyewall surrounding Hurricane Lorenzo as the hurricane was about to make landfall. [NASA Earth Observatory] An earlier image from NOAA's GOES-12 satellite showed Tropical Storm Lorenzo before it reached hurricane status over the southern Gulf of Mexico. [NOAA OSEI]
  A tropical depression formed in the eastern part of the basin near the Cape Verde Islands at the end of last week. By Saturday, it had intensified to Tropical Storm Melissa, the thirteenth named tropical cyclone of the 2007 North Atlantic hurricane season. However, by Sunday, this tropical storm had weakened as it moved to the west northwest and was downgraded to a tropical depression.
- In the eastern North Pacific basin, a tropical depression formed early Saturday and became the tenth named tropical cyclone of the season in that basin by afternoon. As of Sunday afternoon, Tropical Storm Juliette was moving to the northwest across the Pacific well to the west of the Mexican coast.
- In the western North Pacific basin, Tropical Storm Francisco weakened and dissipated over the Gulf of Tonkin early last week. Tropical Storm Lekima formed this Sunday (local time) over the South China Sea west of the Philippines and traveled west toward central Viet Nam.
Record setting loss in Arctic ice documented -- An image obtained from the Advanced Microwave Scanning Radiometer (AMSR-E) Instrument on NASA’s Aqua satellite in mid-September 2007 shows the smallest areal extent of Arctic sea ice in recorded history. A graph shows the seasonal decline in sea ice for this record-setting season, the previous record 2005 season and the long term (1979-2000) average. [NASA Earth Observatory]
Greenland snowmelt reaches record -- NASA scientists at the Goddard Space Flight Center have found that the melting of snow and ice from off the Greenland ice sheet during 2007 has been much greater than the long-term (1988-2006) average. They found that a significant amount of the melting has occurred on high-altitude areas of the ice sheet. [NASA Earth Observatory] See graphics of melting across Greenland. [NASA GSFC]
Heat wave in Canadian Arctic raises concern -- Canadian scientists participating in an International Polar Year research project of the Canadian Arctic claim that the heat wave of this past summer across the territory of Nunavut has lead them to revise their forecasts of the influence that climatic change could have on the region's hydrologic cycle and, ultimately, upon the region's ecosystem. [Queen's University]
Lake in Canadian Arctic affected by climate change -- An international team of researchers lead by scientists at the Université Laval have studied the aquatic life in Ward Hunt Lake, which is North America's northernmost lake in the Canadian archipelago, and conclude that this life has undergone major transformations during the last two centuries attributable to anthropogenic influenced global climate change. [EurekAlert!]
Concerns about rising sea level -- The President of the Maldives, a nation on an Indian Ocean archipelago, recently warned that his nation could become uninhabitable before the end of this century because of projected increases in global sea level unless significant cuts in greenhouse gas emissions are implemented. [Reuters]
Life in Antarctica survived ice ages -- Scientists from the British Antarctic Survey and New Zealand's Massey University report that their research shows the evolutionary history of Antarctica’s terrestrial plant and animal life does not reconcile with current estimates of the glacial ice extent during the past 23 million years. [EurekAlert!]
Increases in carbon dioxide did not end last Ice Age -- An earth sciences professor at the University of Southern California claims that deep-sea temperatures rose about 19,000 years ago, or approximately 1300 years prior to increases in atmospheric carbon dioxide, thereby ruling out the role that this greenhouse gas would have been the primary driver for the end of the last Pleistocene Ice Age. [EurekAlert!]
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: Artificial Snow

Snow is the essential ingredient for many winter recreational activities including downhill and cross-country skiing, snow boarding, and snowmobiling. No natural snow cover means no cross-country skiing or snowmobiling. But ski slope operators have another option if weather conditions do not provide adequate snow cover--they can generate their own snow. Artificial snow is used to build a base for skiing, to refresh snow surfaces, and to make skiing possible even during a snow drought, significantly lengthening the ski season. Some ski areas have the equipment to spread artificial snow over 80% or more of their terrain. Whereas snowmaking offers many recreational and economic advantages, some drawbacks stem from altering the local water budget.

Artificial snow actually consists of tiny particles of ice. Snowmakers use specially designed snow guns into which flexible hoses feed compressed air and water separately. A jet of compressed air breaks the stream of water into a fine mist of tiny droplets, which if conditions are favorable, freezes into ice crystals. Expansional cooling of the compressed air as it is emitted through the nozzle of the snow gun and into the atmosphere chills the water droplets. Artificial "snowflakes" settle onto the slopes and mechanized snow groomers then till and spread the accumulated artificial snow evenly over the ski slopes.

Many snowmakers add a special protein (commercially known as Snowmax) to the air/water mix to improve both the quality and quantity of artificial snow. A non-toxic and non-pathogenic strain of a bacterium produces the protein that attracts water and promotes ice crystal formation. Snowmax increases the amount of artificial snow produced at higher temperatures and snowflakes tend to be drier and lighter than other artificial snowflakes.

Ideal weather for snowmaking consists of low air temperature, light winds, and low humidity. Snowmaking is possible even when the air temperature is above 0ºC provided that the relative humidity is sufficiently low that the wet-bulb temperature is below 0ºC. Recall from pages 65-66 in your DataStreme WES Textbook that the wet-bulb temperature is the reading obtained through evaporative cooling when water vaporizes from the wetted bulb of a liquid-in-glass thermometer. Some droplets in the fine water spray (produced by the snow gun) evaporate, tapping latent heat from the air. With sufficient evaporative cooling, the air temperature drops to the wet-bulb reading, that is, to freezing or below, and subsequent water droplets freeze to ice crystals.

The water demand for snowmaking may impact the local water budget. In Vermont, for example, snowmaking uses about 2 billion gallons of water per year—equivalent to about one-seventh of the volume of the public water supply. To cover an area measuring 500 m by 60 m with 20 cm (8 in.) of artificial snow requires about 2500 cubic meters (658,000 gallons) of water. Streams are the usual source of water for snowmaking but ski areas are typically located high on hill or mountain slopes where stream flow is normally low, especially in winter. In some cases, dams or holding ponds are constructed to ensure an adequate water supply for snowmaking. Diversion of water for snowmaking may cut the supply of water for users downstream. Water that is stored in the winter snowpack on the ski trails runs off to streams during the spring snowmelt, adding to the normally high spring stream discharge and perhaps increasing the potential for downstream flooding.

Concept of the Week: Questions

If the air temperature were above 0ºC, artificial snow can be made if the wet-bulb temperature were [(above) (below)] the freezing point of water.
When water droplets evaporate while falling through a layer of relatively dry air, the temperature of the surrounding air [(falls) (rises)].

Historical Events

1 October 1976...Hurricane Liza brought heavy rains and winds to Brazos Santiago, Mexico, causing a dam to break on the Cajoncito River, which killed 630 people as a wall of water crashed into the town of La Paz. (The Weather Doctor)
1 October 1893...The second great hurricane of the 1893 season hit the Mississippi Delta Region drowning more than 1000 people. (David Ludlum)
1 October 1997...Flash flooding in Nogales, AZ resulted from 2 to 3 inches of rain. One hundred homes and 30 businesses were flooded and five vehicles floated down Western Avenue. (Accord Weather Calendar)
2 October 1867...A hurricane struck Galveston, TX with a storm tide that caused $1 million damage. (Intellicast)
2 October 1882...A major hurricane struck the Louisiana Delta with 100-mph winds and 12-foot storm tide which inundated the bayous resulting in 1500 deaths. (Intellicast)
2 October 1898...A hurricane struck the Weather Bureau (now National Weather Service) hurricane observation post at Carolina Beach, North Carolina and swept away the office's outhouse. The storm became known as the "Privy Hurricane". (Northern Indiana NWSFO)
3 October 1841...The "October Gale," the worst of record for Nantucket, MA, caught the Cape Cod fishing fleet at sea. Forty ships were driven ashore on Cape Cod, and 57 men perished from the town of Truro alone. Heavy snow fell inland, with 18 inches near Middletown, CT and 3 inches at Concord, MA. (David Ludlum)
3 October 1912...The longest dry spell of record in the U.S. commenced as Bagdad, CA went 767 days without rain, ending on 9 November 1914. (David Ludlum)
4 October 1869...A great storm struck New England. The storm reportedly was predicted twelve months in advance by a British officer named Saxby. Heavy rains and flooding plagued all of New England, with strong winds and high tides along the coast of New Hampshire and Maine. Canton, CT was deluged with 12.35 inches of rain. (David Ludlum)
4 October 1986...Excessive flooding was reported along the Mississippi River and all over the Midwest, from Ohio to the Milk River in Montana. In some places, it was the worst flooding of record. Rainfall totals for the week included 20.07 inches at Hale, KS, nearly 18 inches at Coffeyville and Walnut, KS. (Sandra and TI Richard Sanders - 1987) (Intellicast)
5 October 1786...The famous "Pumpkin Flood" occurred on the Delaware and Susquehanna Rivers. Harrisburg, PA reported a river stage of twenty-two feet. The heavy rains culminated a wet season. (David Ludlum)
5 October 1972...Heavy rains, mostly the remnants of Tropical Storm Joanne, fell across much of Arizona. It was believed to be the first time in Arizona weather history that a tropical storm entered the state with its circulation still intact. The center was over Flagstaff early on the 7th. (3rd-7th) (The Weather Channel)
5-7 October 1999...A storm southeast of New Zealand caused surf to reach heights of 12 feet along the south shores of all the Hawaiian Islands, flooding some roads and parking lots. The lobby of the Kihei Beach Resort on Maui and three ground floor units were flooded. (Accord Weather Calendar)
6 October 1967...Canada's 24-hour rainfall record was established at Ucluelet Brynnor Mines on Vancouver Island in British Columbia with 19.24 in. (Accord Weather Calendar)
7 October 1737...A furious cyclone in the Bay of Bengal caused a major disaster at the mouth of the Hoogby River near Calcutta, India. As many as 300,000 people were killed, mainly as the result of the storm's forty foot high surge. (Accord Weather Calendar)