Already 400,000 Lebanese are on the roads as refugees. Israel yesterday ordered the population in the South below the Litani river to leave by 6pm and Beirut has been attacked for the first time since 1982. Lebanese and Syrian soldiers are among the casualties. The Israeli navy is blockading the port of Beirut.
Israel said yesterday that it would stop its offensive as soon as it had strict guarantees that Hizbollah, the Lebanese guerrilla movement, would stop firing Katyusha rockets into Israel.
But the very size of operation "Grapes of Wrath" means the political future of Lebanon and the role of the outside powers with an interest there - Israel, Syria and Iran - has been thrown into the melting pot.
So far, all is going well for Israel. It has suffered no military casualties and only one civilian has been seriously wounded. World public opinion seems largely unmoved. Above all, the US is giving unqualified support and puts all blame on Hizbollah for provoking the attacks by firing Katyusha rockets at northern Israel.
International acquiescence may not last - particularly if there are more incidents such as the Israeli helicopter attack on a Lebanese ambulance which killed four children - but it allows Israel time to carry out a prolonged operation which may last for two weeks or more.
The danger for Shimon Peres, the Israeli prime minister, is that this is as good as it is going to get. "There was no great euphoria in the halls of the defence ministry," writes commentator Nahum Barnea of the mood in the political and military establishment. "Everyone, first and foremost Peres, is waiting for a counter-attack."
So far there has been little sign of resistance by Hizbollah. It has lobbed some Katyusha rockets into northern Galilee. But it has launched no ground attacks. Against artillery and air strikes there is little it can do, but retaliation is bound to come. The organisation has called for its suicide bombers to assemble. In the weeks before "Grapes of Wrath" Hizbollah units showed great skill in infiltrating behind Israeli lines and can presumably do so again.
The Israeli operation has a number of related objectives. It is a collective punishment of the population of south Lebanon who support Hizbollah. It is unlikely, however, that it will turn them against the guerrillas since such punishments have been inflicted before, without the desired effect. Although Israel says it is destroying Hizbollah targets the guerrillas do not depend on arsenals, drill halls and emplacements.
A second objective is to force the Lebanese government to take stronger measures against Hizbollah. To this end the economic recovery of Lebanon is being crippled. The port of Beirut and ports to the south are blockaded. Maybe Rafiq Hariri, the Lebanese prime minister, does not have much control over Hizbollah, but the Israeli government wants him to put pressure on Syria to curb the guerrillas. The idea is that President Hafez al-Assad can be forced to agree to new rules preventing Hizbollah from firing Katyushas at Israel.
There is a third, largely unspoken, objective for Mr Peres. This is to win the election on 29 May. No Israeli government ever lost votes by waging war successfully against an Arab enemy. For the moment the campaign in Lebanon looks well timed to redress fears in the Labour party that Mr Peres will suffer at the polls because he is seen as soft - too much the civilian diplomat - compared to Binyamin Netanyahu, the leader of the right wing Likud party and his rival for the prime minister's office.
It could all come unstuck. Israel is playing its trump cards now. Hizbollah, to retain its credibility, will have to strike back effectively. In the past it has shown it can do so. "Israel with this move is trying to restore its aggressive image which has been tarnished in recent years," writes Alu Ben in the daily Ha'aretz. But Syria and Iran back Hizbollah and are unlikely to accept its humiliation by Israeli without a response.
Israel believes that its intelligence is better and munitions more accurate than during 1993, the last time it raided Lebanon during "Operation Accountability". This may be so, but few guerrilla forces have been seriously damaged by air and artillery attacks alone, as the US learned in Vietnam.
A ground assault by the Israeli army would be dangerous. It would mean casualties, with damaging political consequences in Israel, and it would lead to a much more hostile international and Arab reaction to "Grapes of Wrath".