Israel-Hamas conflict: Impending sense of crisis in Gaza as Israel urges more than a million people to flee

There is an impending sense of crisis in Gaza as more than a million people rush to escape. 

It comes after Israel warned 1.1 million people in Gaza to leave their homes and flee immediately.  

It's the latest sign that it's preparing a ground invasion, a move the United Nations (UN) warms could be "calamitous".   

Even the most innocent in this war are being forced to flee for their lives. The people of Northern Gaza don't have a choice or time to decide.  

On Friday night Israel gave 1.1 million of its people a deadline, to get out and head south.  

Parents are being forced to grab their children and take them from the only home they've ever known.  

Cars now line the streets, with whatever belongings they have inside, some even tying their possessions to the roof. Choosing to stay may be a death sentence.  

In between the missiles, Israel has dropped leaflets with a warning.  

"For your safety do not return to your homes until further notice", the leaflets read.  

The Israeli Defence Force has not revealed why its urging residents not to return home, but a look over the border might reveal the answer. 

Columns of military tanks sit ready for what may be a brutal ground invasion.  

"The aim here is to minimise the damage to civilians, there are significant combat operations, and we are preparing for the future," said Israeli Defence Force spokesperson Lieutenant Colonel Jonathan Conricus.  

Israel has ordered 1.1 million people in Northern Gaza to head south, past a river valley. There's only one highway heading south, and much of it is damaged from missile strikes. 

The river they've been ordered to cross only has one major bridge, to leave Gaza altogether, the only hope they have is the Rafah Crossing controlled by Egypt. 

Though, so far, Egypt has not allowed Gazans through.  

The United Nations acknowledges what seems like an "impossible" situation. 

UN deputy spokesman Rolando Gomez is urging Israel to avoid a "humanitarian catastrophe". 

"The United Nations considers it 'impossible' for such a move to take place without devastating consequences."  

Hamas has told Palestinians to stay and ignore Israel's "psychological warfare", but those choosing to leave, do so after watching their homes bombarded, and the bodies piling up. 

After a week of strikes, Israel's Prime Minister Benjamin Netanyahu offered a chilling warning. 

"It's only, the beginning."