When making a successful Stealth check it becomes unseen and unheard and it's location beccome unknown as others loose tracks of him.
<snip>
Trying to hide is a Dexterity check and succeeding makes the elf's location unknown as well as being unseen and unheard. I'd think of it as camouflage, nothing magical about it.
But what is happening in the fiction if a person is looking at an elf through the snow, and then - at the gaming table - the player of the elf declares "I hide" and rolls a DEX check and gets a result higher than the observers passive Perception?
I think it is possible that the snow swirls around the elf, making him/her vanish from sight. Another possibility is that, at the behest of the elf, the snow briefly flurries into the eyes of the observer, rendering him/her a non-observer. But then I'm puzzled why it is a DEX check.
Even if it's camouflage - eg the elf's skin changes colour (not something I've ever heard suggested, but at least a logical possibility) - that doesn't explain why it would be a DEX check. (I assume that noone thinks that the elf is applying greasepaint to him-/herself, or rapidly changing clothes, and that
that is why it's a DEX check.)
I gather that [MENTION=6787503]Hriston[/MENTION] thinks that none of these scenarios is a possibility within the fiction - though I'm yet to get a reply myself to that question. To my mind, it seems to depend not on the wording of the rules - which are not specific enough on these issues - but rather on how one envisages things taking place in the fiction.
(In post 407, [MENTION=23751]Maxperson[/MENTION] says "It's a hide check, so yes it would be a dex check", but that doesn't really answer the question: it doesn't tell us what is happening in the fiction.)
you usually know someone's location before it successfully hide, that's why it is usually best to move after you do. Again hiding doesn't strickly is having your location concealed, but also being unseen and unheard.
This brings up a point that I think needs more attention. In this discussion, people have been tossing around the notion of "knowing location" as if it were a simple binary proposition. I think it is not. As I see it there are (at least) two complications.
Here is a RL example.
Me to my wife: Where are my keys?
Wife: Right there on the counter?
Me: Where?
Wife: Right there! Beside the calendar.
Me: Uh...I don't see them.
Wife (rolling her eyes walking over and pick them up): Right! Here!
Another one (I was a tanker):
Tank Commander: Gunner, Coax, Infantry in the tree line (this is the command to fire the coax machine gun at a specific target)
Gunner: I don't see them
TC: Right where your sight is pointing. Tree line, 200 meters.
Gunner: I don't see them (fires anyway in the general area and gets disadvantage on the shot)
Defining hidden as location unknown rather than unseen and unheard excludes these scenarios from the game.
I've been assuming that ((at least in this discussion, which is about whether or not things are hidden or perceived) by "knowing the location" is meant something along the lines of "knowing in virtue of
perceiving", not simply "knowing in the sense of
believing because told by someone else who is reliable". There's a whole literature on this (it's modern version begins with the famous 1963 paper by Gettier), and on whether we should call the second sort of thing "knowledge" at all (in a 1912 book that predates the modern iteration of the discussion, Bertrand Russell called the second sort of thing "probable opinion").
You just came in, declared that you hadn't read the thread and then started arguing from one definition while completely ignoring the other. That is the context my first comment below./Edit
No. A million times. No. What is happening is Hriston, Flamestrike and others are arguing from one definition of "hidden" that is not supported by the rules (made even more clear when Jeremy Crawford's Safe Advice on the subject is read without ignoring the context of the question he was answering). Another definition of hidden is unseen and unheard and this definition makes the rules more clear and Mr. Crawford's Sage Advice make more sense.
I don't really think it's that big a deal if two people who (most likely) have never met, and certainly aren't going to be playing D&D together, have different views about when an elf can and can't become hidden in a snow storm.
This has been a subject of disagreement - in part because of ambiguous rules wordings, but in part also because people have different views about what is happening in the fiction - going back to the thief ability to hide in shadows.
Consider, for instance, the rules text from Gygax's PHB (pp 27-28) and DMG (p 19):
Hiding in shadows is the ability to blend into dark areas, to flatten oneself, and by remaining motionless when in sight, to remain unobserved. It is a function of dress and practice. . . . [It] cannot be accomplished under direct observation. . . . Success makes the thief virtually invisible until he or she moves.
[T]this is NEVER possible under direct (or even indirect) observation. If the thief insists on trying, allow the attempt and throw dice, but don't bother to read them, as the fool is as obvious as a cool pile in a ballroom. Likewise, if a hidden thief attempts movement while under observation, the proverbial jig is up for him or her. Naturally, a creature closely pressed in melee is not
likely to bother with looking for some thief not directly in the line of sight, but if vision would normally extend to the thief's area of activity, then observation rules apply. Unobserved attempts to hide in shadows must likewise stand the hazard of the dice roll. A score greater than the required number shows that the character's ability is not on a par with his or her intent, and although he or she THINKS hiding has been successful, the creature looking in that direction will note a suspicious outline, form, or whatever.
On the one hand, this is the ability to be "virtually invisible" and "to remain unobserved" even when "in sight", provided the thief remains motionless. On the other hand, it is "NEVER possible" under observation.
How to resolve the apparent contradiction? This seems to be left up to each table - my preferred reading is that a thief who enters the shadows while under observation cannot successfully hide, but one who is already in the shadows and remaining motionless can remain hidden, even if a would-be observer's gaze falls on him/her, provided that the d% roll is successful.
Now, relating this to the current discussion (and I'd be curious to hear [MENTION=6787503]Hriston[/MENTION]'s views on this - I suspect that, like me and perhaps some others here, Hrisotn is fairly familiar with the AD&D hide in shadows rules): it's one thing to say that an elf who is concealed in a snowstorm is hard for an observer to spot (ie is entitled to make a DEX check to remain hidden although the storm is not heavy enough to conceal ordinary people); it's a different thing to say that an elf who is
being observed through a snowstorm can suddenly - by magic, as it were - render him-/herself invisible.
Which takes us back to the question - what form does that magic take? and why is it modelled, mechanically, by a DEX check?
I think the Sage hints at an answer to the first question - nature itself conceals the elf - but other things are unasnwered, like "Does nature answer the elf's call at will?" and if so, why a DEX check?
I mentioned JRRT's elven cloaks upthread. In the case of these, the wearer doesn't get to choose - the cloak conceals him/her, and then once s/he choose to become visible the jig is up (until the observers look away). I am guessing that this might be how [MENTION=6787503]Hriston[/MENTION] envisages the elf's ability working: as soon as it starts snowing the elf becomes hidden (though we may not actually roll the DEX check until later on when we need to know whether or not another can spot him/her). And if the elf subsequently, or nevertheless, comes under observation, then s/he is not hidden to that observer until something happens that makes the observer (even momentarily) lose sight of her. And the mere continuation of snow falling wouldn't be such a "something".