Saturday, November 7, 2009

The picture above shows one of the siren towers that made up Portland's attack warning system back in the 1950's. These sirens were to sound if Russian bombers carrying H-bombs were headed on a bombing mission to our city.

Below, a map shows the strategic placement of the 7 sirens throughout the city. Each circle radius is 10,000 feet or about 2 miles.

Thursday, November 5, 2009

Cold War reminder: SW 32nd and Texas Hydropark

These 2 concrete footings are all that remain of the air warning tower that was placed here back in 1953. The mounting studs have been cut flush with the top of the concrete block, but you can see where the tower legs used to sit.

This is the only remnant left from Portland's Cold War air raid warning sirens.

Wednesday, November 4, 2009

The photo above shows the position of each air raid siren in the city of Portland in 1953. These 7 giant sirens replaced a system of 50 air horns used as an air raid warning following the Korean War. The super sirens formed a perimeter around the city in the following locations: in St. Johns at N. John and Princeton St; N Portland: Emerson and Maryland St; NE Portland at NE 57th Ave and Sandy Blvd; Downtown: on the roof of the American Bank building on SW 6th Ave and Morrison; SW Portland at SW 32nd and Texas; SE at McLoughlin Blvd and Milwaukie Ave; the last one was located on SE 54th Ave and Boise St. The sirens were placed 2 to 3 miles apart which covered most of the city back then.

This tower was located on SE 54th Ave and Boise St

The picture above shows the installation of a siren on top of a tower in 1953. A 30-ton crane was used to lift the siren onto the 12 ft x 12 ft tower platform. The towers were 50-feet high and made of steel. The sirens sat on a circular track that allowed a 360-degree traverse. Each siren weighed approximately 5000 pounds. The towers weighed approximately 8500 pounds. The towers were prefabricated at Swan Island by Thompson Metal Fab and trucked to their locations where they were placed on concrete footings. The siren on top of the downtown bank was the first operational warning siren. The siren located at SE 54th and Boise was the second one completed. The Sandy tower was the third one finished. There were a total of six siren towers erected in 1953. Of the six additional sites other than the bank building, 5 of the lots were owned by the city or Multnomah County and one was owned by the
Southern Pacific Company.

The giant sirens were made by the Chrysler corporation. Each siren was equipped with a 331 cubic inch 180-horsepower Hemi gasoline engine. The sirens would rotate 360 degrees on top of their platforms and were capable of producing a wail of 138 decibels each. These sirens were the most powerful sirens ever made and could be heard from a distance of 10 miles. In 1953, the cost of an air raid siren was $5500. The total cost per siren and tower was about $10,000 each.

Initially, the sirens were tested every Monday at noon. After the public outcry became louder than the sirens, they were tested once a month until they were eventually taken down.

Air Raid Siren Time Line

1951 Korean War prompts air horn warning system to be reactivated
1951 Air horn system tested and fails
1951 Planning begins for 7 siren warning system network
1952 City Council approves siren warning system sites
1953 Downtown siren mounted on top of American Bank
1953 6 towers and sirens placed in positions around city perimeter
1954 All sirens operate in unison for first time
1955 Operation Greenlight (civil defense evacuation)
1957 CBS documentary "Day Called X" is released
1962 Columbus Day Storm exposes Civil Defense System as ineffective
1963 Portland withdraws from the Federal Civil Defense System
1963 Siren warning system ceases operations
1964 Emergency Broadcast System on radio and tv replaces CONELRAD
1964 Air raid sirens are "pickled" = batteries removed and gas tanks drained
1965 Removal of sirens and towers
1971 Siren auctioned off and sold for $60 to private party

The picture below shows the 50-foot high air raid siren and tower located at SE Milwaukie Ave and McLoughlin Blvd. You can see Oaks Bottom in the distance.