It started with them already on the beach, and some getting to the yacht, with fire and bombing in the backdrop. The implication is that in the hours in between the break, they started bombing the city.

 

on the aftershow, it was stated that only a few hours had passed

therefore, when Strand showed Matt Abigail in the binoculars it was approx. mid-afternoon, the beach scene was probably 4 hours later when they showed the jets flying towards burning LA dropping napalm/bombs whatever

there are too many people in LA which equals too many zombies for the survivors to contend with on land

 

that was the beginning of the show. kinda weird, right? im surprised they really didn't segway into that a little better from where we left off. i actually felt like those first 5 minutes were really cheesy. people just standing around and letting zombies get really close to them and then fighting them off without taking any damage. the propeller kill was way over the top IMO. cheesy horror flick stuff.

 

I'm fairly certain taht 5 minutes was there to draw in casual new viewers who didn't watch season 1. It was like 5 minutes out of Z-Nation.