There is a crack, a boom and a siren, all more or less simultaneously. Sergio Helman has not quite reached the concrete shelter a dozen metres away from his hummus restaurant, off highway 99, which marks the northernmost limit of the northern Israeli town of Kiryat Shmona.
The 60-year-old shrugs and explains that Hezbollah fires the rockets from so close that Israeli air defence systems can give only 15 seconds warning at best.
