Developing and Communicating Warnings

1. Developing and Communicating Warnings Sarah Davies UK Met Office Wednesday 17th April 2013

2. In this session • Using the UK Met Office National Severe Weather Warning Service (NSWWS) as an example • Understand what makes a weather warning effective • Essential elements of an effective warning • Communicating warnings • Communicating uncertainty • Verifying warnings

3. Effective What makes a weather warning effective

4. Criteria for issuing a warning • Need to find out • what types of weather affect the general public and emergency/disaster responders • If it doesn't affect them, do you need a warning? • Establish and research • which types of weather need a warning and why • how much rain has to fall or how strong does the wind need to be to warrant a warning? • if thresholds or potential impacts are the best measure for issuing a warning

5. Thresholds 20mm/hr 30mm/hr 40mm/hr 10mm/24hr 50mm/24hr 50mph gusts 60 mph gusts 2m tidal surge Impacts Saturated ground/Large puddles Flooding of agricultural land from rainfall/ from river bursting banks/coastal Flooding of road networks from rainfall/ river bursting banks/coastal Flooding of towns/cities from rainfall/ river bursting banks/coastal Trees blown down/boats overturned/ power cables brought down Criteria for issuing a warning Which is more important?

6. History of NSWWS Great Storm 1987

7. UK Severe weather • Severe Gales • Heavy Snow • Heavy Rain • Dense Fog • Freezing rain/widespread icy roads • Heat wave Exceptionally severe when: • Severe gales/storms • Very heavy snowfall, blizzards, drifting snow All based on meteorological thresholds

8. National Severe Weather Warning Service • Warns community of severe or hazardous weather • Widespread disruption of communications • Transport difficulties • Threat to lives, welfare, property

9. National Severe Weather Warning Service THREE TIERS • ADVISORY • Issued daily at around11am • EARLY WARNING • Issued several days in advance of the severe weather (typically 3-5 days) • FLASH • Issued when the severe weather is imminent (up to 6 hours in advance)

10. Severe/Extreme • Severe weather – these events are not unusual and are experienced on a number of occasions throughout the year, but more commonly winter months. They will impact on individual areas, but often not significantly. • Extreme weather – these events are unusual and only happen around 3 or 4 times per year. They have a significant impact on infrastructure and may lead to casualties.

11. Early Warnings • Issued in advance of the expected severe weather (typically 3-5 days) • Assessment of the risk of disruption when it is above 60% • Each region is assigned percentage risk of disruption (impact based) • Disruption map published on website • Allows time for preparations to be made • Once issued, updated daily until the event

12. Early Warning on the web 1/2/09

13. Flash Warnings • Issued when the severe weather is imminent (target of 2 hours, up to 6 hours in advance) • Issued if certain critical meteorological thresholds are likely to be met with an 80% probability • Issued on county/local authority basis • React to rather than prepare for

14. An evolving process In 2009, we asked our stakeholders about: • Usefulness of warnings • Timeliness • Clarity

15. We worked with partner agencies to develop a risk matrix The alert/warning will provide a combination of The potential impact the weather will have The likelihood of the weather happening NSWWS since 2011

16. Likelihood • Allows us to communicate uncertainty • In general uncertainty is greater at longer lead times • Most alerts at 3 to 4 day lead time will be assigned a low/very low likelihood

17. Generic Impacts

18. Impactshttp://www.metoffice.gov.uk/weather/uk/advice/ Other impacts specific to rain, wind, ice and fog also listed.

19. Colour of warnings (Impact Matrix) • Colour determined by combination of likelihood and impact • Matrix below shows a high likelihood of a medium impact event produces an AMBER warning

20. Severe Weather WarningsColour Codes

21. Interpreting the colours • ‘Be Aware’ means • Remain alert and keep up to date with latest forecast • ‘Be prepared’ means • Remain vigilant, keep up to date with latest forecast and take precautions where possible • ‘Take action’ means • Remain extra vigilant, keep up to date with latest forecast. Follow orders and any advice given by authorities and be prepared for extraordinary measures

22. Impacts • Important to ascertain which impact column is being used • Do not get into habit of dismissing yellow warnings/alerts • “it’s only a yellow” • Yellow could be a very low likelihood of high impacts

23. Access to warnings • All warnings/alerts appear on the Met Office website and Hazard Manager • http://www.metoffice.gov.uk/public/weather/warnings/ • Amber and Red Warnings are sent to Category 1 and 2 responders via a self registration scheme • Email- pdf • Email- plain text • SMS • Can select up to 3 emails, 1 sms, and 1 fax

24. Snow • Ice • Strong Winds • Fog • Heavy Rain

25. National Severe Weather Warning Service • Sent to ~850 organisations • Over 2,500 delivery points, including… • Blue Lights (Police, Fire and Ambulance) • Central, regional and local government • NHS • Utilities • Media Cascaded through individual organisations

26. Warnings on the webHomepage ticker banner

27. UK Warnings

28. Chief Forecasters Assessment

29. Communicating our forecasts and warnings - UK • Met Office website • Text and email alerts • Public Weather Service • TV and radio • You Tube • Twitter • Facebook • Flickr • Blog • Mobile Phone / Apps

30. Public Appreciation 90% of the public think Met Office weather warnings are useful

31. Communicating our forecasts and warnings • Met Office forecasts are broadcast on: • BBC TV • BBC National Radio • BBC Local Radio • BBC websites • ITV and other commercial TV networks • Commercial Radio • Newspapers

32. BBC Weather Centre

33. We have two BBC TV studios

34. Verifying warnings • Why do we need to? • What do we need to know? • How can we develop a severe weather database • Example from Met Office/UK • How could you do it in your country?

35. Why? • What happened? • Did we forecast it? • At the right time • In the right place • What were the impacts? • Was the warning communicated effectively • Improve understanding, better warning next time

36. What do we do? • Verification • Objective verification • Did we issue a warning when a threshold was exceeded? • Subjective verification • Did the warning give good advice • What happened? What were the impacts….

37. Subjective verification • Verifying the impacts • Media reports • Twitter feeds • Impacts reported by responders • Verifying the usefulness • Right place? • Right time? • Enough lead time? • Good advice?

38. On Call Log

39. How do we do it ? • On call log • Verification folder

42. How do we do it ? • On call log • Verification folder • Meetings each month • All data kept

43. How could you do it? Things to think about • How could you develop a severe weather database? • What are your issues? • How could you collect severe weather information from remote corners of the country?

44. Recap • The National Severe Weather Warning Service uses a combination of LIKELIHOOD and IMPACT to give a single colour • Easy to understand • Aims to change peoples behaviour • Use a variety of methods of communication • Verification is important to continually improve • Work with stakeholders….

45. Questions?