Electric cars use high tech lithium batteries. These batteries are dangerous in a variety of situations but they're also full of electronics to compensate. If anything at all bad happens (for example, a short circuit due to water) the battery itself will shut down, and you'll have to get the car towed.
Cars are expected to handle all kinds of weather and Ford is a reputable company. I would expect all high voltage power sources to be perfectly protected from water splashing up from the wheels which would mean shallow water is fine. If the water gets up into the doors though, then you might be in trouble.
Doing some research, I found someone who's nissan leaf that was submerged for an extended period it of time (the water was half way up the door, wheels totally under water) and the car computers had detected various faults and shut everything down. A mechanic cleaned things up as best they could and the car was able to start, but more errors were detected so they declared the car a write off.
My guess is that car could have been repaired if it was taken to a more competent mechanic, but most mechanics don't know anything about electric vehicles and they're not going to risk telling you everything is fixed when they honestly don't know.
Tesla says that there is no safety risk at all if the car is fully submerged in water, but obviously it would destroy the car just like happened with the Leaf. If the battery catches fire they recommend using "large amounts" of water to cool the batteries down. You're likely to need to keep the battery cool for up to 24 hours, so make sure you have a lot of water available to keep the batteries cool.
My understanding is water won't put out a lithium battery fire, but it should prevent the fire from spreading into neighbouring battery cells, and eventually the ones already burning will run out of fuel.