That has happened to me twice. Once on a Chevy Van and most recently on a 1995 Ford F-150. Both times it was the heater core that needed to be replaced.
What causes heat to only come out of the defrost and vent but not the floor of a 1995 S10 Blazer?
A bad heater core / it needs to be replaced
could be a vacuum line off
It should only be steam.
To get a boost from a steam vent, walk to the middle of the steam vent and then jump up. If you jump onto the steam vent from the top, it won't boost you up as high.
Turn the defroster on. If you have a separate AC switch, turn it on also. The AC should come on with the defroster automatically, but might not. If no AC, set the vent control to outside air instead of recirculate.
It is on above of right vent the button is there on the top of middle vent console
A geyser is a natural vent that discharges steam or water from Earth.
In the center of the dash at the defroster vent.
Lava
only if the steam is not allowed to vent properly.
A vent in the earth's crust through witch lava, steam, ash, and etc come poring out.