In brief: if you hear thunder or see lightning, the activity must cease and participants must immediately seek shelter. If 30 minutes passes without further thunder or lightning, the activity may resume. If thunder or lightning recurs, the clock starts over. If the activity is a game, the game must end prior to the official start time of the next game.
From the Guidance for Referees, Coaches, Other Volunteers and Parents – 2011 (pg 47):
What procedure should be followed regarding electrical storms? Thunder and Lightning Storms A lightning safety plan should be an integral part of the planning process for any outdoor event. Do not wait for storm clouds to develop before considering what to do should lightning threaten! An effective plan begins LONG before any lightning threat is realized. The key to an effective lightning safety action plan lies in answers to the following questions:
Where is the safest lightning shelter?
How far is the group from that location?
How long will it take to get the group there?
Knowing the answers to these questions and formulating a plan of action accordingly will likely reduce the chances of anyone being struck by lightning.
If a Region has frequent thunderstorms, that Region should consider posting a safety policy on the Region’s Website, discussing it in Safe Haven® courses, emphasizing at all coach, referee and team parent orientation meetings and putting it in the Region Handbook distributed to participating families.
In tournament play or other special events, if there is a possibility of thunder and lightning storms, a pre-event meeting to discuss guidelines, safety procedures, duties and responsibilities of all event staff and participants should be conducted. A communication plan should also be considered so this information can be given to all participants and volunteers in order to execute emergency planning procedures.
Event officials will consult and determine the course of action – give the “all clear” sign for games to resume, cancel the balance of ongoing games or cancel games for the day. Event administrators, Regional Commissioners or their designees, including Coach Administrator, Referee Administrator or Referees, should have the authority, as so designated, to delay the start of play, call a halt in play or suspend/terminate a game due to severe weather conditions.
Most people are struck by lightning before and after storms have peaked, not at the height of a thunderstorm. Lightning often strikes miles from the area of rain. Please be aware of how far lightning can strike from its originating thunderstorm.
See also pages 32 & 33 of the AYSO Safe Haven Certification Manual for 2010-2011.
The United States Soccer Federation (USSF) position is that if you can hear thunder you are within reach of lightning and that referees must protect the safety of all participants by stopping game activities quickly, so that participants and spectators may retire to a safer place before the lightning threat becomes significant. Applying the 30-30 rule is recommended and to wait thirty minutes or more after hearing the last thunder before leaving shelter.
In view of the above, the following is the position of the AYSO National Referee Advisory Commission regarding severe weather: “It is said that lightning can strike from a clear blue sky that is within a ten mile radius of a storm. It is therefore strongly recommended that practices and games be terminated immediately upon hearing thunder or seeing lightning. “If you can see it - flee it; if you can hear it – clear it.”