Can you drop concentration on the Reverse Gravity spell while the targets are mid-fall?

Question

When you cast the spell Reverse Gravity (5e), creatures start falling upwards into the air. Assuming that there is nothing in their way the spell must somehow halt their momentum when they reach the top of it, as the spell says "If an object or creature reaches the top of the area without striking anything, it remains there, oscillating slightly, for the duration." If it didn't halt their momentum somehow, they would fall up into normal gravity for another 100 feet or so, and then almost all the way back to the ground (with real world physics anyway; air resistance would be the only thing that slowed them down, and that would only remove about 5 feet worth of momentum per 100ft fall- I did the math).

Because of this I'm assuming that the spell stops momentum when the creatures hit the top of the spell area somehow.

But what happens if you drop concentration on the spell while they are falling upwards? The condition "If an object or creature reaches the top of the area without striking anything" no longer applies, as the spell isn't in effect anymore. Physics tells us that the creature falling upwards 100 feet in a reversed gravity field would then have enough momentum to 'fly' another 100 feet upwards beyond that until slowing to a stop and falling back down (discounting air resistance). So lets say you dropped concentration just before they reached the top of the spell area; would they then fly up to a height of 200ft off the ground before then falling to the ground for 20d6 damage?

I know you can drop concentration as a free action anytime, but this spell doesn't seem to indicate how it works exactly regarding the momentum gathered while falling upwards. I'm wondering if the above interpretation is reasonable?

Answer 1

The D&D rules largely ignore physics, and things do only what they say.

Because of that guiding principle, we should be able to figure out a RAW interpretation using the text of the spell.

The full text of the reverse gravity spell reads (emphasis mine):

This spell reverses gravity in a 50-foot-radius, 100-foot high cylinder centered on a point within range. All creatures and objects that aren’t somehow anchored to the ground in the area fall upward and reach the top of the area when you cast this spell. A creature can make a Dexterity saving throw to grab onto a fixed object it can reach, thus avoiding the fall.

If some solid object (such as a ceiling) is encountered in this fall, falling objects and creatures strike it just as they would during a normal downward fall. If an object or creature reaches the top of the area without striking anything, it remains there, oscillating slightly, for the duration.

At the end of the duration, affected objects and creatures fall back down.

The bold portion means that the effect of the spell (save, floating, reaching the top) all happens instantaneously by RAW.

It is completely understandable that players and Dungeon Masters would want to make things a bit more realistic in their own games, but should know that this can lead to many unbalanced and unforeseen consequences. You can find many stories dealing with that across the internet. Some groups enjoy that kind of thing more than others.

Answer 2

As noted in this question, there are no explicit rules for the speed at which you fall, except for an optional rule that states that you instantly fall 500ft per turn (far more than the range of this spell)

This seems to agree with the way the spell is written: objects and creatures fall upward and reach the top of the area when you cast this spell. Instantly.

RAW, I read that as the fall happening instantly and not give anyone time to do anything else... with the exception of a Dexterity saving throw, that allows to grab onto an object and avoid the fall. So you cannot end concentration mid-fall, and the scenario you are asking about cannot happen.

So, the Reverse Gravity spell seems to work as follows:

1. Someone casts the spell.
2. Creatures that have a nearby fixed object they can grab onto make a Dexterity saving throw.
3. Every creature and object that failed the saving throw or could not take it (or chose not to) instantly falls upward, taking damage for every object or creature that they strike during the fall.
4. Falling creatures reach the top of the area of effect (100ft) and float there.

I do not like that, RAW, "If an object or creature reaches the top of the area without striking anything, it remains there, oscillating slightly, for the duration.", as it is unclear to me why striking anything should affect the final outcome of falling, and I honestly do not know how to interpret that, so I ignored it.