Impact Based Warnings Enhancing Weather Warnings to Include Impacts Information

Jim Allsopp NOAA/, Chicago DuPage Advanced Spotter Training March 16, 2013 Why Impact Based Warnings?

• 2011 Annual Totals – 1,691 tornadoes (3 rd most) – 550 fatalities (4th deadliest) – Most fatalities since 1936 • April 27, 2011 – 300 tornadoes, 15 EF4/5’s – 316 fatalities (4th deadliest day) – Despite average warning lead time of 25 minutes • Joplin, MO May 22, 2011 – EF5 , 158 killed – Despite initial warning lead time of 23 minutes Why Impact Based Warnings? Service Assessment Key Findings:

• Many people identified sirens as their first source of warning.

• Many people sought confirmation from additional sources before seeking shelter.

• Credible, extraordinary risk signals prompt people to take protective actions.

• Perception exists “sirens go off all the time and nothing happens”.

• There was a lack of, or inconsistent use of, enhanced wording in warnings during known significant events (Tornado Emergency).

• The existing weather enterprise dissemination system is not fully compatible with storm-based warning polygons. Why Impact Based Warnings? Why Impact Based Warnings? Not all tornadoes are created equal!

We have one product to let people know a tornado is coming, whether it is for this

or this!

5 Why Impact Based Warnings? Not all tornadoes are created equal!

We have one product to let people know a tornado is coming, whether does this or this!

• We need to design hazardous weather awareness with a scale, rather than our current yes/no paradigm 6 Impact Based Warnings 2012 Demonstration Project

• 5 NWS Weather Forecast Offices • Wichita, KS • Topeka, KS • Kansas City/Pleasant Hill, MO • Springfield, MO • Saint Louis, MO • Apr – Nov, 2012 Impact Based Warnings

Goals: • Provide additional valuable information to media and Emergency Managers • Facilitate improved public response and decision making • Better meet societal needs in the most life-threatening weather events Impact Based Warning Experimental Product Independent Evaluation: • Performed by the group Weather and Emergency Management (WxEM) • Using focus groups and surveys • Media partners • Emergency Management • Public • NWS Forecasters Evaluation Results

• 2012 - Drought year with fewer tornadoes, limited use of tags

• April 14, 2012 outbreak yielded good information

• NWS made enhancements and expanded evaluation area to entire NWS Central Region for 2013

10 On April 1, 2013 – Expands to All NWS Central Region Impact Based Warnings

• What are the changes? • Tornado Warnings – Tag at bottom of TOR warning • Tell you if a tornado is “observed” or “radar indicated” • Also information about tornado damage threat – Additional hazard information in 3 rd bullet • Sources and impacts • Severe Warnings – Tag at bottom of SVR warning • Already have “Wind” and “Hail” tags • Will add “Tornado…Possible” in certain situations • Start Date: April 1, 2013 Identity Tags

• Tornado “Identity Tag” at bottom of • Same spot as “hail size tag” – “Radar Indicated” • “Developing” or “Rotation” terms used – “Observed” • Various sources, but a reported tornado from human observation – Radar also showing evidence at the same time – What if Radar doesn’t help to substantiate report? – Also included at bottom on Severe Weather Statements for tornado warnings (SVS) Damage Threat Tags

• Tornado “Damage Threat” Tags – At bottom of Tornado Warnings – “No Tag” • Most of the time (80+% of the time???) • Radar indicated/developing • Limited knowledge of damaging impacts • Rural areas – “Tornado Damage Threat…Considerable” • Used rarely. Confirmed stronger tornado. – Term used in 2012 was “significant”. 2013 term is “considerable” – “Tornado Damage Threat…Catastrophic” • Akin to “tornado emergency” • Exceedingly rare. 1 or 2 times in 30 year career? Changes to Damage Tags

• Tornado “Damage Tags” – May change during the warning • Could start with “radar indicated” AND “no tag” • May end up with “observed” AND “considerable” damage threat – Information is included in severe weather statements (SVS) subsequent to the warning • Includes enhanced wording in the body of the warning (tag or no tag) Enhanced Wording

• Enhance Wording is in all tornado warnings, in 3 parts 1. Hazard – Developing tornado (and hail) – Confirmed tornado 2. Source – Radar vs. confirmed 3. Impact – Special impact statements IBW – Impact Statements

Impact statement for BASE tornado warning: : Significant house and building damage possible. Mobile homes completely destroyed if hit. Some trees uprooted or snapped. Vehicles will likely be thrown by tornadic winds.

CONSIDERABLE tornado warning: Major house and building damage likely and complete destruction possible. Numerous trees snapped. Major power outages in path of tornado highly likely. Some roads possibly blocked by tornado debris. Complete destruction of vehicles likely.

CATASTROPHIC tornado warning (Tornado Emergency): This is a life threatening situation. You could be killed if not underground or in a tornado shelter. Complete destruction of entire neighborhoods is likely. Many well built homes and businesses will be completely swept from their foundations. Debris will block most roadways. Mass devastation is highly likely making the area unrecognizable to survivors. Enhanced Wording

• Designed to elicit response, especially for more significant situations – Not an attempt to predict tornado intensity – Not an attempt to assess tornado rating – Will not alleviate some issues • Still False Alarms (or perceived false alarms) – You may still be within warning area and not get hit by the tornado itself – Actions by people are often “individualistic” in nature • Not sure just how each person will react Severe Thunderstorm Tag

• Additional “tag” to some, not all, Severe Thunderstorm Warnings • Currently…tags for expected largest hail size and expected highest wind speed – Add a tag of “Tornado…possible” – “A severe thunderstorm has some potential for producing a tornado although forecaster confidence is not high enough to issue a Tornado Warning.” Severe Thunderstorm Tag

• Most Severe T-Storm Warnings will not have a “tornado” tag – Most will just contain “hail” and “wind” tags – Severe T-Storm Warnings will not routinely mention widespread, major damage • Exceptions are 80-90-100 mph type wind events – Probably larger events (several counties/large line of storms) – Probably not likely to illicit the same “response” as tornado warning tags Summary of Tags Impact Based Warnings Samples Tornado Warning

Radar indicated

No damage tag Tornado Warning

Observed

No damage tag Tornado Warning

Observed

Considerable damage tag Severe Weather Statement

Tornado warning follow up

Radar indicated

No damage tag Severe Weather Statement

Tornado warning follow up

Observed

Considerable damage tag

CONSIDERBLE Severe Thunderstorm Warning

Tornado Possible

Wind and hail Tag Impact based Warnings Potential Issues • Many warning systems (e.g. TV crawls) just use coding to disseminate info – Warning type – County(ies) affected – Expiration time • Siren policy – Many dispatchers need a yes or no decision 2013 IBW - Review

• Beginning Date: April 1, 2013

• NWS Chicago and all NWS offices in the Central Region will participate

• 2013 will be an “operational” evaluation period – We need your feedback 2013 – IBW Review

• 2013 = Impact Based Warning (IBW) goals

1. Improve the communication of risk

2. More clearly identify potential impacts

3. Use of “tags” in warning message for important information (EMs, media, etc) 2013 – IBW Review

• Emergency Management and Broadcast Media – Look for the tags to help understand risk and “uncertainty” aspects of the warning • Quick way to help understand the storm threat – In the RARE cases of considerable or catastrophic damages expected… • Remember…point is to convey risk to those in the path. • Not a prediction of tornado rating or strength necessarily – Catastrophic damage is similar to “Tornado Emergency” and will be very, very RARE Impact Based Warning

In summary, enhancements provided by: • Improving communication of critical information • Making it easier to quickly parse out the most valuable information • Enabling users to prioritize the key warnings • Providing different levels of risk within the same product • Enabling the NWS to express a confidence level of potential impacts and risks Impact Based Warning

Intended Outcomes: • Optimize the convective warning system within the existing structure • Motivate proper response to warnings by distinguishing situational urgency • Realign the warning message in terms of societal impacts • Communicate recommended actions/precautions more concisely • Evaluate ability to distinguish between low impact and high impact events Questions?

Jim Allsopp [email protected] http://weather.gov/chicago