Transportation

Geography

Historical Background

Identified Hazards

Issues

Maps

Jefferson County has seven incorporated communities: Hamer (pop. 12), Lewisville (467), Menan (707), Mud Lake (270), Rigby (2,998), Ririe (520), and Roberts (647). The total population for the county in 2000 was 19,155. That is an increase of 16% since 1990.

Transportation

Geography

Land Area: 1,106 square miles. 

Historical Background

Established February 18, 1913 with its county seat at Rigby. Named for Thomas Jefferson, third president of the United States. The first settlers were Mormons who constructed irrigation systems. .

County Seat: Rigby

Wind -   April 23, 2002

Event Summary:    $4,500,000.00 - The Snake River Plain area in SE Idaho experienced a severe windstorm on April 23, one week after a heavy snowstorm.  Sustained winds between 40-50 mph were recorded, with gusts reaching 60-70 mph,  The area affected ranged from Minidoka to Pocatello , Craters of the Moon, Blackfoot, Idaho Falls to Rexburg.  10,000 residents lost power in Blackfoot, Pocatello and Chubbuck. Schools were closed in Jefferson County .  Poor visibility and blowing dust closed roads, including I15 from Idaho Falls to Roberts; Hwy 20 from Arco to INEEL; Hwy 26.  Homes and power lines received extensive damage from falling trees and blowing debris.

County Summary:  

Flood - March-July, 1997

Event Summary:    $50,000,000.00 - Rapid melt of a record snowmelt led to flooded rivers throughout southern Idaho .  The Snake River Basin received significant snowfall during the winter of 1996-97, and in higher elevations the snow pack exceeded 250% of normal, causing above normal runoff during the spring melt.  Reservoir flows were increased to allow storage capacity, producing  the highest flows on the Snake River in 70 years.  During June, the spring snowmelt caused extensive flooding along 225 miles of the Snake River and many of its tributaries, from Roberts to Blackfoot.  In places, floodwaters ran as far as a mile away from the river and 5' deep.  Damage was extensive to numerous roads, canals, farmland and over 300 homes.   A Federal Disaster was declared on July 7, 1997 , for seven counties in SE Idaho :  Bingham, Bonneville, Fremont, Jefferson , Madison , Butte and Custer.  Approximately 500 people were evacuated in Jefferson and Bingham counties; more than 50,000 acres of agricultural land was flooded; and over nearly $1.3 million in grants and loans had been distributed.  Increased flows on the Boise River damaged sections of the Greenbelt .

County Summary: Idaho 48 was closed for use as an evacuation route for Roberts residents fleeing the flooding waters of the Snake River. - $659,000.00

Interagency Hazard Mitigation Team Report; Idaho Transportation Department

Severe Weather - 1/6-2/5/89

Event Summary:  A blizzard ripped through eastern Idaho blocking several highways, closing schools, and prompting avalanche warnings. Severe winds and blizzard conditions kept ranchers from reaching livestock resulting in great losses.

County Summary: Severe winter prompted a disaster declaration from livestock losses resulting from the severe storm in January and February.

The Idaho Statesman 1 April 89

Severe Weather - 1/1989

Event Summary:  A disaster declaration for severe winter.  Heavy snowfall in January and February caused severe livestock loss.

County Summary:  Severe winds and blizzard conditions kept ranchers from reaching livestock

Idaho Statesman 1 April 89

Frost - Fall 1985

Event Summary:   Potato Crops were damaged do to early fall frosts.

County Summary: Potato Crops were damaged do to early fall frosts.

Flood -  6/13/1984

Event Summary:    Mud lake floods near disaster.

County Summary: State of emergency was declared when Mud Lake flooded threatening 15,000 acres of farmland and 20 homes.

The Idaho Statesman 13 June 1984

Flood - Teton Dam Failure -  June 5, 1976

Event Summary:    $1,000,000,000.00 - It was the unleashed fury of 80 billion gallons of water.  It began the morning of 5 June 1976 when early in the morning a whirlpool appeared behind the dam.  Then around 11, a small hole appeared in the dam itself with water seeping through, two workers tried to fill the hole but to no avail.  They ran to safety and a few minutes before  noon the water rushed through a gapping break.  11 people lost their lives.

County Summary: Farms and buildings destroyed- 1,277, Acres damaged- 17,456; livestock lost- 1,450; equipment (in dollars)- $6.5 million; businesses destroyed or damaged-26; homes destroyed-45 mobile; homes damaged-285; Lost hunting days (in dollars)- $27,413; TOTAL DAMAGE- $25,000,000.00

The Idaho Statesman and Fish & Wildlife

Flood -  February 10-14, 1962

Event Summary:    $15,000,000.00 - Floods were touched off when prolonged rain and warm temperatures combined to melt mountain snowpacks and send the runoff rushing into the lowlands faster than the still frozen ground could absorb.  A federal disaster declaration was issued  2/14/62 after extensive flooding along the Portneuf River and its tributaries, The Snake and Teton Rivers, inundating an area from Sugar City to Malad and from Aberdeen to Soda Springs.  Throughout the area, numerous earthen dams and levees collapsed, roads were closed, bridges damaged, houses and businesses flooded.  National Guard and Army Corps of Engineers responded to the areas in hopes of stopping additional flooding.  Damage was estimated at more than $15 million.  Damage to over 1500 homes was reported.

County Summary: 3 homes affected by the floods.  3000 acres of farmland were flooded, most of it being alfalfa.

The Idaho Statesman 18 Feb 1962

Flood -  5/29/1956

Event Summary:  Flooding of the Upper Snake River and Salmon Rivers .

County Summary: Several hundred acres of farm land near Menan were flooded from 1-6 feet of water.

Lewiston Morning Tribune 30 May 56

Identified Hazards ( Most likely to occur & greatest impact)

Other Issues