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The Wall of Ice spell creates ice that can block movement:

You create a wall of ice on a solid surface within range.

In real life, ice can be either clear or opaque, depending on factors such as the presence of internal debris and air bubbles.

Is the Wall of Ice opaque and blocking vision? Or is it possible to see freely through the Wall?

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    \$\begingroup\$ Are you a player, or are you DM looking for advice? \$\endgroup\$ – Mołot May 17 at 10:12
  • \$\begingroup\$ @PurpleMonkey That's a perfectly fine answer! \$\endgroup\$ – NautArch May 17 at 12:17
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It is up to the DM.

Compare the description of other "Wall of ..." spells.

Wall of Fire's description says:

[...] The wall is opaque and lasts for the duration.

Wall of Force's description tells us that when you cast this spell

An invisible wall of force springs into existence at a point you choose within range. [...]

The Wall of Light

[...] blocks line of sight, but creatures and objects can pass through it.

The Wall of Sand specifies that

It blocks line of sight but not movement.

The Wall of Thorns

[...] blocks line of sight.

We can conclude that if a Wall of ... spell prevents vision (as mentioned in an example here) or affects it in some way, it is clearly stated in its description, or can be inferred by the material of which the wall is made of (e.g., Wall of Stone). Since Wall of Ice (together with Wall of Water and Wind Wall) does not have any indication, this is left to the DM, which may rule in a way or another, or even let the player decide.

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    \$\begingroup\$ Given that the other spells specify that limitation, wouldn't lack of that specificity be meaningful? \$\endgroup\$ – NautArch May 17 at 13:22
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    \$\begingroup\$ @NautArch The Wall of Stone is the real counter-example here, as it's the other Wall spell that doesn't call out whether it blocks sight, presumably because they assume we know that you can't see through stone. That kind of implies the devs thought it was obvious whether or not you can see through ice, but heck if I know which one they were thinking. \$\endgroup\$ – Darth Pseudonym May 17 at 13:58
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    \$\begingroup\$ @Medix2 I did not include Prismatic Wall, since it consists of several layers and it is not made of only one material/element. It looks to me "different" with respect to the other Walls of spells. \$\endgroup\$ – Eddymage May 17 at 14:49
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    \$\begingroup\$ What if I make a wall of stone out of Ulexite? \$\endgroup\$ – Kirt May 17 at 15:37
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    \$\begingroup\$ @Kirt As I wrote, the ruling about vision and line sight can be inferred by the material of which the wall is made of, and again it is up to DM, hoping they have proficiency in geology :-) \$\endgroup\$ – Eddymage May 17 at 15:44
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If I were the DM in this situation, I'd apply physics principles (but certainly not calculations).

  • If we go with ice has a low enough opacity to see through, then it doesn't block line of sight, but it changes the perceived location of the target, which the visual aids demonstrate.
    • I would consider allowing players with an affinity for water, like Water Genasi, or as part of a metamagic feat, to select the level of opacity of the wall (e.g. 0% being transparent).
  • The Wall of Ice or Water, does not block line of sight in the traditional sense of a rock blocking the line of sight, but the target will not be in the position it appears to be in, because light refracts at the surfaces.
  • In the case of a Wall of Ice, which can have a curved or flat surface, refraction is going to hinder line of sight even more.
  • In practical terms, I'd probably apply some level of cover to the target, or allow the target a saving throw bonus.

Through two flat surfaces

enter image description here

Through a sphere

enter image description here

Equivalent to a hemispherical dome

enter image description here

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Edit. Rereading the question, I see that OP was using "blocks line of sight" in the colloquial sense of "unable to be seen through," not necessarily in the rules sense of "unable to be targeted by a spell." I'll leave my answer because I hope it addresses a possibly useful subquestion.


In the Players Handbook Chapter 11, Spellcasting, it says the following about spell targets:

A Clear Path to the Target

To target something, you must have a clear path to it, so it can't be behind total cover.

If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

So it seems to be that the default rule for a wall is to block line of sight for purposes of choosing targets, unless the effect says otherwise — as other answers have pointed out it's the case with some other Wall of X spells.

Similarly, for areas of effect:

A spell's effect expands in straight lines from the point of origin. If no unblocked straight line extends from the point of origin to a location within the area of effect, that location isn't included in the spell's area. To block one of these imaginary lines, an obstruction must provide total cover, as explained in chapter 9.

The rule for total cover given in Chapter 9 is:

Total Cover

A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle.

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  • \$\begingroup\$ My original title was "Is a Wall of Ice opaque?", but it got changed for unknown reason by Eddymage. \$\endgroup\$ – Guillaume F. May 17 at 22:27
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    \$\begingroup\$ @GuillaumeF. Actually I just removed a comma, Akixkisu changed the title. You can check all the modification done on your question/answer and you may even roll back to previous versions. \$\endgroup\$ – Eddymage May 18 at 6:37
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As Jeremy Crawford explained...

Rules do what they say they do.

The General Rule that applies to ALL objects including walls related to line of sight is on PHB 183:

lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) checks that rely on sight

heavily obscured area—such as darkness, opaque fog, or dense foliage—blocks vision entirely. A creature in a heavily obscured area effectively suffers from the blinded condition (see appendix A)

So unless the Wall of Ice is determined by the DM to be an object that provides lightly obscured(like light fog) or Heavily obscured (like dense fog) then since there is no mention that it blocks line of sight.... it does not.

Plain and simple

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    \$\begingroup\$ As noted in other answers, Wall of Stone doesn't say it blocks line of sight either. But I think we can safely say that it should. \$\endgroup\$ – ShadowRanger May 18 at 22:58
  • \$\begingroup\$ @ShadowRanger as also mentioned in the comments, what if you make a wall of stone out of Ulexite? \$\endgroup\$ – Ekadh Singh May 19 at 15:37
  • \$\begingroup\$ @EkadhSingh: It's pure sophistry; "Wall of Stone" is not the same as "Wall of Cut and Polished Crystal of the Absolutely Perfect Quality Necessary to Have It Conduct Light Through Six Inches of it Such That It's Translucent At Best". May as well ask what happens if you make your Wall of Stone out of diamond. \$\endgroup\$ – ShadowRanger May 19 at 15:43
  • \$\begingroup\$ I added the general rule for vision that directs every object in the game. so unless a specific rule in a spell states something about vision. the general rule applies. Wall of Stone is an object that produces heavily obscured (blocks vision entirely) wall of ice a DM could decide what obscuration it is, but the spell does not specify it does block line of sight so it does not in itself but must be determined by the object specifications as any other object. \$\endgroup\$ – KilrathiSly May 20 at 22:47

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