I was thinking of using piping gel and food color, but the cake has to travel 3 hours in the car. So I was thinking may be the piping gel will fall off, so I was thinking royal icing but I love shiny effect of the piping gel. Any tips on making the waterfall effect. It will be on a tiered cake. Will piping gel work? Thanks

I've done several cakes with waterfalls on them. I usually use buttercream on the base and make a "swirl effect" with my fingers, then use a moderate amount of royal blue piping gel. I've prepared it the day prior and traveled only about 1 1/2 hours with it and had no problems.
Good luck!

thank you so much

there is a little mermaid cake in my pictures that I have the waterfall and I used piping gel and I have never had a problem with it running. I usually put it on with a little brush so it is not real heavy. hope this helps