Tornado Siren Location: Ann Arbor, Michigan

Abstract

Different strategies for locating systems of sirens exist in different locales across the nation. In Ann Arbor, and elsewhere, sirens noise is designed to alert citizens in the outdoors. Citizens who are indoors may hear the sirens but the requirement is that people outdoors be able to hear them. Thus, spacing requirements between sirens becomes important. When there are barriers to overcome (all else being equal), such as topography, buildings and street noise, one might expect sirens to be required to be more closely spaced than in flat, open countryside. Indeed, a brief review of municipal requirements on the world wide web reveals that Oakland County, Michigan views each siren to be capable of covering about a one mile radius. The Baltimore City Fire Department selects spacing at 3200 feet. The sequence of animaps below, of Ann Arbor, suggests a locational strategy for pinpointing positions for new sirens.