The "Download Now" link directs you to the iTunes App Store, where
you must continue the download process. You must have iTunes installed
in order to open the link, and you must have an active iTunes account to
download the application. This download may not be available in some
The purpose of Flash Boom is simple. It will give you an estimate of how far away lightning is. The rule of thumb says to allow about 5 seconds for each mile (3 seconds for each kilometer). In reality it is more like 4.72 seconds per mile and 2.99 seconds per kilometer.