Hazard Warnings GE 4150 Natural Hazards September 17 2007 http www sdr gov NDIS rev Oct27 pdf Sorensen J H 2000 Hazard warning systems Review of 20 years of progress Natural Hazards Review May 119 125 1 How has prediction and forecasting improved technology major improvements hurricanes nuclear accidents minor improvements volcanoes flood earthquake 2 How has warning integration merging of monitoring detection social factors to issue alerts information improved conversion to EAS planning study of myths effectiveness 3 How has warning dissemination improved clearer chain of command technological advances public awareness 4 What do we know about responses to warnings hazard organizations need a clear role physical public response known but not psychological Recommendations create a national warning strategy improve existing warning systems improve and equalize understanding for range of hazards Sorensen J H 2000 Hazard warning systems Review of 20 years of progress Natural Hazards Review May 119 125 Modeling warning dissemination and response Officials slow in reaching decisions Most of the population at risk can be notified within 3 hours New warning systems can achieve very rapid warning The time people spend in responding to a warning depends on the perceived urgency of the threat The time required to evacuate a population is unrelated to the size of the population Examples of warning failures March 27 1994 A tornado killed 20 worshipers at a Palm Sunday service at the UMC Goshen Church in northern Alabama A warning had been issued 12 minutes before the tornado struck the church Though it was broadcast over the electronic media the warning was not received by anyone in or near the church The region was also not covered by NOAA Weather Radio February 22 23 1998 Unusually strong tornadoes occurred in east and central Florida during the late night and early morning killing 42 The NWS issued 14 tornado warnings which received wide distribution by the electronic media and NOAA Weather Radio The warnings were not widely received as people were asleep and did not own tone alert NOAA Weather Radios May 31 1998 A tornado killed six in Spencer South Dakota A warning was issued but the sirens failed to sound because the storm had knocked out the power Again the area was outside reception of NOAA Weather Radio Emergency Alert System EAS Digital replaced Emergency Broadcast System in 1994 Activated local state national hundreds of times each year At national level only the president can issue an EAS A special officer accompanies the president at all times to contact FEMA which then activates the EAS Once the president uses it FEMA can use it to distribute information State and local officials can request EAS activation for emergencies FCC coordinates all EAS activities related to industry station inspection review of all national state and local EAS plans FEMA coordinates all EAS activities related to government NWS prepares and issues warnings for extreme weather events Glossary Affected people total affected Dead Estimated Damage Homeless total affected Injured total affected Miscellaneous accident Explosions Collapses Fires Total affected injured affected homeless Measures of performance of the National Weather Service warnings Warnings Tornado Lead Time mins Accuracy 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Est Est Est Est Est Est 6 43 7 45 10 60 10 59 10 59 11 66 12 70 12 70 13 70 13 70 14 72 15 74 16 70 17 72 17 75 18 82 18 82 18 84 19 84 20 85 21 86 22 87 23 88 24 89 22 71 70 18 47 64 26 60 64 39 79 41 45 82 37 52 85 35 41 82 27 46 86 26 48 86 24 50 87 23 55 88 22 58 89 20 82 65 82 65 84 72 85 74 86 76 86 77 87 78 87 80 88 82 88 82 89 83 89 84 37 39 42 44 45 50 55 60 65 70 70 72 2 1 2 2 2 3 2 3 2 3 2 3 2 3 2 4 2 4 2 5 2 5 2 6 111 191 81 90 44 84 81 81 78 78 75 Severe Thunderstorms Lead Time mins Accuracy Flash Flood Lead Time mins Accuracy No Lead Time Temperature Correct forecast Accuracy of Forecast Onset of Freezing Temp Snow Amount Forecasting Heavy Snow Precipitation Lead time days for 1 forecast vs 1 day accuracy in 1971 Hurricanes Accuracy of landfall miles w 24 hr lead time Effective warning messages should Be brief typically less than two minutes and preferably less than one minute Present discrete ideas in a bulletized fashion Use nontechnical language Use appropriate text graphics geared for the affected hazard community and general population Provide official basis for the hazardous event message e g NWS Doppler Radar indicates tornado police report of chemical accident etc Provide most important information first including any standardized headlines Describe the areas affected and time e g pathcasting for moving events such as weather systems volcanic debris or element dispersal etc Provide level of uncertainty or probability of occurrence Provide a brief call to action statement for appropriate public response e g safety instructions for protection of life and property any evacuation instructions shelter or other care facilities etc Describe where more detailed follow up information can be found USGS Level of Concern Color Code for Volcanoes Green Volcano is in its normal dormant state normal seismicity and fumarolic activity is occurring Yellow Volcano is restless Seismic activity is elevated Potential for eruptive activity is increased A plume of gas and steam may rise several thousand feet above the volcano which may contain minor amounts of ash Orange Small ash eruption expected or confirmed Plume s not likely to rise above 25 000 feet above sea level Seismic disturbance recorded on local seismic stations but not recorded at more distant locations Red Large ash eruptions expected or confirmed Plume likely to rise above 25 000 feet above sea level Strong seismic signal recorded on all local and commonly on more distant stations http volcanoes usgs gov Products Warn warn html Lahars Uses acoustic flow monitor stations installed downstream from a volcano Each stations has a seismometer analyzing ground vibrations and a microprocessor that analyzes the signal http volcanoes usgs gov About What Monitor Hydrolo gic LaharDetect html A radio at the station sends and receives information from a base station A battery and solar panel powers the system An emergency message is sent any time the vibrations exceed a given threshold for longer than 40 seconds Used at Mount Rainier Washington Project coordinating USGS and Pierce County http volcanoes usgs gov