Tuesday, July 13, 2010

Oregon at Risk

Check this link for information on each region.


Regional Profile Overview

The Oregon Coast region has experienced an 5.3% increase in population since 2000. This represents a lower rate of growth than other regions of the state. Just over half of the region's population lives in incorporated areas. Thirty percent of the region's houses were built before 1960, 35% between 1960 and 1980, and 35% were built after 1980. Transportation networks are an important consideration for the coastal region given the physical boundary of the ocean to the west and the Coast Range to the east. The average commute for workers in this region is 22 minutes each way. Most bridges in the area have not been seismically retrofitted, creating significant risk to the commuting population from earthquakes. Historically, the fishing, lumber and wood products industries dominated this region, but those industries have been surpassed by service sector jobs and retail. The median income for residents of region 1 in 2007 was $38,183. This is below the national average of $50,007 and the state's average of $47,385.

Regional Hazard Assessment Overview

Region 1 has a high probability of being affected by a tsunami, earthquake, flooding, landslides, wildfire, or windstorms. It has a low probability of being impacted by volcanic hazards.

The geographical position of Region 1 makes it highly vulnerable to earthquakes from several sources, but the off-shore Cascadia Subduction Zone could cause the greatest damage. The last large earthquake recorded - though not a subduction event - was a magnitude 7.3 in 1873 with an epicenter near the City of Brookings. Tsunamis typically occur as secondary hazards to earthquakes, or occasionally due to underwater landslides. In 1964, Cannon Beach, Coos Bay, Depoe Bay, Florence, Gold Beach, and Seaside were struck by a tsunami generated in Alaska, thereby incurring over half a million dollars in damage and resulting in four fatalities. In Region 1 there can be a moderate to high level of vulnerability to tsunamis below 100 feet MSL.

High winds can be expected throughout Region 1. Gusts exceeding 100 miles per hour are fairly common at several coastal locations during winter storms. The most famous of these storms is the 1962 Columbus Day storm that had recorded winds over 130 mph on the coast and resulted in 23 fatalities. The vulnerability to windstorms in the region is high to moderate, mitigated to some extent by building code provisions that account for high winds.

Three types of flooding occur in this region: riverine, ocean flooding from high tides and wind-driven waves, and flooding associated with a tsunami event. Repetitive flood events have impacted the City of Tillamook, exceeding the base flood elevation numerous times, including 1996, 1998 and 1999. FEMA later re-mapped the floodplain in the City of Tillamook, and the 100-year base flood elevation is higher in some areas along north Highway 101. Most of the counties in Region 1 have a high probability of flooding. Heavy rainstorms also typically cause landslides. The vulnerability to landslides is high to moderate.

Region 1 is less vulnerable to drought impacts than most of Oregon, but droughts can still be problematic, especially given that they often precede major wildfires. Severe drought conditions resulted in the four disastrous Tillamook fires (1933, 1939, 1945, 1951), collectively known as the Tillamook Burn. There have been a number of long droughts throughout the last century, as well as a drought during 2001. While the region's vulnerability to drought is low, its vulnerability to wildfire is considered high to moderate.

For more information on previous occurrences of hazard events, as well as the probability of future hazard events as estimated in local risk assessments, download the full regional profile.