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Ridges, Valleys and a Wildfire in the Area of Knoxville, Tennessee, USA

35.9N 83.9W

November 13th, 2009 Category: Fires, Lakes, Rivers

USA - November 8th, 2009

USA - November 8th, 2009

The city of Knoxville in the state of Tennessee, USA, is visible as a greyish circular area in the lower left quadrant, near a series of hills and ridges. These are part of the Appalachian Ridge-and-Valley Province, which consists of a series of elongate and narrow ridges that traverse the upper Tennessee Valley.

Also of note in this image is a wildfire in the upper left quadrant, the smoke from which is blowing northeast. The fire is located in the state of Kentucky, not far from the Tennessee border.

The most substantial Ridge-and-Valley structures in the Knoxville area are Bays Mountain, which runs along the Knox-Blount county line to the south, and Beaver Ridge, which passes through the northern section of the town. The Great Smoky Mountains— a subrange of the Appalachian Mountains— are located approximately 20 miles (32 km) south of Knoxville.

In the southeast part of the city, the French Broad River joins the Holston River to form the Tennessee River. Knoxville is centered around a hilly area along the north bank of the river between its First Creek and Second Creek tributaries.

Two lakes are visible northeast of Knoxville. The first, Douglas Lake, also called Douglas Reservoir, is an artificial lake created by an impoundment of the French Broad River by Douglas Dam. The dam was built by the Tennessee Valley Authority in the early 1940s to control flooding in the Tennessee Valley and provide electricity to rural areas in the region. The lake, easily identified by it’s snakelike bends, is situated only a few miles from the Pigeon Forge/Gatlinburg area and the Great Smoky Mountains National Park.

The second body of water, just north of Douglas Lake, is the Cherokee Reservoir, also known as Cherokee Lake, formed by the impoundment of the Holston River behind Cherokee Dam, which was built for hydroelectric generation and flood control. The reservoir has a surface area of about 28,780 acres (11,650 ha), a flood-storage capacity of 749,406 acre feet (924,379,000 m3), and nearly 400 miles (640 km) of shoreline. In a normal year, the lake water level fluctuates over a range of about 27 feet (8.2 m).

Ida Upgraded to Category 2 Hurricane, Moving Into Southern Gulf of Mexico – November 9th, 2009

21.7N 87.1W

November 9th, 2009 Category: Image of the day, Tropical Storms

Hurricane Ida - November 8th, 2009

Hurricane Ida - November 8th, 2009

Track of Ida - November 8th, 2009 © Univ. of Wisconsin

Track of Ida

Enhanced image

Enhanced image

As of 3:00 PM CST (2100 UTC), the center of Hurricane Ida was located near latitude 22.2 north, longitude 86.3 west, or about 95 miles (155 km) west-northwest of the western tip of Cuba and about 510 miles (815 km) south-southeast of the mouth of the Mississippi River.

Ida is a category two hurricane on the Saffir-Simpson scale, although the system is forecast to gradually weaken on Monday. Here, the hurricane is visible near the coast of the Yucatan Peninsula, with part of the shoreline of Florida visible to the north.

Ida is moving toward the north-northwest near 10 mph (17 km/hr). A gradual turn toward the north and an increase in forward speed are expected during the next 24 to 36 hours. On the forecast track, Ida is expected to cross the Gulf of Mexico Sunday evening and Monday and be near the northern Gulf coast on Tuesday.

Maximum sustained winds are near 100 mph (160 km/hr) with higher gusts. Hurricane force winds extend outward up to 35 miles (55 km) from the center, and tropical storm force winds extend outward up to 140 miles (220 km). The minimum central pressure is 976 mb (28.82 inches).

Ida is expected to produce total rain accumulations of 3 to 5 inches over portions of the Yucatan Peninsula and western Cuba, with possible isolated maximum amounts of 10 inches. Rains will be increasing well in advance of Ida across the central and eastern Gulf coast, but will become steadier and heavier by Monday into Tuesday. Total storm accumulations of 3 to 5 inches with isolated maximum storm totals of 8 inches will be possible through Tuesday from the central and eastern Gulf coast northward into the eastern portions of the Tennessee Valley and the southern Appalachians.

A storm surge could raise water levels by as much as 3 to 4 feet above ground level along the coast of the Yucatan Peninsula. Near the coast, the surge will be accompanied by large and destructive waves.

A hurricane watch remains in effect for the northern Gulf coast from Grand Isle, Louisiana to Mexico Beach, Florida, and the Yucatan Peninsula of Mexico from Tulum to Playa del Carmen. This watch does not include the city of New Orleans. A hurricane watch means that hurricane conditions are possible within the watch area, generally within 36 hours.

A hurricane warning remains in effect for the Yucatan Peninsula of Mexico from Playa del Carmen to Cabo Catoche, meaning that hurricane conditions are expected somewhere within the warning area within 24 hours. Preparations to protect life and property should be rushed to completion in the warning area.

A tropical storm warning remains in effect for the Yucatan Peninsula Punta Allen northward to Playa del Carmen and from Cabo Catoche westward to San Felipe, as well as for the Cuban province of Pinar del Rio. A tropical storm warning means that tropical storm conditions are expected within the warning area within 24 hours. Finally, a tropical storm watch remains in effect for the Isle of Youth.

Mississippi and Tennessee Rivers, USA

34.7N 88W

August 15th, 2009 Category: Rivers

USA - June 24th, 2009

USA - June 24th, 2009

The  Mississippi River, appearing greenish brown, winds its way almost vertically across the left side of this image of the USA. The tan terrain around it is part of the Mississippi River Alluvial Plain, which includes parts of seven states.

Moving eastward, another river is visible in the Tennessee Valley by the Blue Ridge Mountains (part of the greater Appalachian Mountains): the Tennessee River. Here, it appears golden yellow from sediments and sun glint; this coloration makes it easier to observe various reservoirs created by dams along its course.