white smoke

[Steve85]

I would start with a cooling system pressure check. If it doesn't hold and there is no external leak well...that's a good sign there is an internal leak. If it is internal, take out the plugs and hit the starter and look for coolant being pumped out of the cylinders. In fact you better do that first when you get home; if the gasket is that bad it will seep into the cylinder while sitting. This will also prevent a hydro-lock if it is indeed leaking internally.

Now a blown head gasket will often pump a lot of coolant in to the exhaust where it can take a while to burn off.

If the cooling system holds pressure, let it run for awhile and see if it burns off. If there is another problem there is not much harm in this, ultimately the tools come back out.