- Thunderstorms approaching from west - Possible impacts: Breaking of branches, toppling of individual trees. Lightning strikes and/or damage caused by hail. Landslides on steep slopes, sudden flash flooding of streams and floodings. - Recommendations for action: Stay away from water and avoid mountain ridges and peaks, trees, masts and towers, as well as open terrain (e.g. clearings, football pitches), all of which are at risk of lightning strikes. In open terrain, if lightning strikes nearby, assume a crouched position (with your feet closed) with as little of your body as possible touching the ground (do not lie down flat).