I'm running the Tyranny of Dragons version of Rise of Tiamat for some friends, and in chapter 10: Sea of Moving Ice, under General Features of the Ice Caves on page 115 it states, "There are no stairs inside the iceberg; the floor slopes between areas of different elevation. Characters can slide down a one-level ramp with ease. Sliding down a two-level ramp (for example, from area 10 to area 9) is automatic if the character is sitting, but requires a DC 10 Dexterity (Acrobatics) check if the character tries to slide down while standing. Characters equipped with crampons cannot stand, but can treat ramps as difficult terrain. Moving along a two-level ramp with crampons also requires a successful DC 12 Dexterity (Acrobatics) check. Characters without crampons can climb a one-level ramp with a successful DC 15 Dexterity check, or can climb a two-level ramp with a successful DC 20 Dexterity check. Acrobatics is of no use to these checks, but using a climber’s kit grants advantage on the checks. Any failed Dexterity check to move on a ramp results in the character sliding to the bottom of the ramp and falling prone."

I find this extremely confusing for several reasons. (For reference, my players were insightful enough to purchase climber's kits and fashion crampons ahead of time knowing they'd be going somewhere made of ice.)

Point of confusion 1: One-level vs. two-level ramps. The example given for a two-level ramp is area 10 to area 9, a difference of 10 feet. Does that then mean that all surfaces are technically ramps? Is a one-level ramp just a numbered area without a change in elevation?

Point of confusion 2: Crampons cramping style. Why is it more difficult to descend a two-level ramp wearing crampons if their entire point is to embed into ice and enhance traction? Also why can't characters stand while wearing crampons? "Sliding down a two-level ramp (for example, from area 10 to area 9) is automatic if the character is sitting, but requires a DC 10 Dexterity (Acrobatics) check if the character tries to slide down while standing. Characters equipped with crampons cannot stand, but can treat ramps as difficult terrain. Moving along a two-level ramp with crampons also requires a successful DC 12 Dexterity (Acrobatics) check."

Point of confusion 3: One-level vs. two-level ramps (part 2). If based on the descriptions of ramps in the beginning of the paragraph, a one-level ramp has no change in elevation, then why are there checks to "climb" it?

Point of Confusion 4: Cramped Again. How do crampons effect climbing ramps? It says, "Characters without crampons can climb a one-level ramp with a successful DC 15 Dexterity check, or can climb a two-level ramp with a successful DC 20 Dexterity check. Acrobatics is of no use to these checks, but using a climber’s kit grants advantage on the checks." It mentions climber's kit, but not crampons.

This seems like pretty bad editing for logic. I think it would make far more sense if a one-level ramp was any 10 ft. elevation change, for example area 10 to area 9, and a two level ramp were any 20 ft. change, fit example area 2 to area 7. I think the rules for a sitting slide make sense. I think the rules for descending ramps are backwards: it should be DC 10 Dex (Acro) for crampons and DC 12 Dex (Acro) for a standing slide. The climbing rules without crampons make sense, but I think crampons should either impart advantage on those checks, or lower the respective DCs by 2.

Anyone that's ran this ice cave, your input is greatly valued.

I agree. Seems like it should read more like:
"There are no stairs inside the iceberg; the floor slopes between areas of different elevation. Characters can slide down a one-level ramp with ease. Sliding down a two-level ramp (for example, from area 10 to area 9 11) is automatic if the character is sitting, but requires a DC 10 12 Dexterity (Acrobatics) check if the character tries to slide down while standing. Characters equipped with crampons cannot stand slide, but can treat ramps as difficult terrain. Moving along a two-level ramp with crampons also requires a successful DC 12 10 Dexterity (Acrobatics) check. Characters without crampons can climb a one-level ramp with a successful DC 15 Dexterity check, or can climb a two-level ramp with a successful DC 20 Dexterity check. Acrobatics is of no use to these checks, but using a climber’s kit grants advantage on the checks. Any failed Dexterity check to move on a ramp results in the character sliding to the bottom of the ramp and falling prone."

We just finished this section of the adventure in my group. After a while I just ignored the DEX checks in going in-between areas. IMO, they have crampons and the "ramps" are so long anyway that the slope is gradual so after a couple tries of it, the PCs have figured out how to navigate them without the need for a check.

Crampons mean that you don't need to have the Dex check.

Climbing Kit without crampons means that you get to make the Dex check with advantage.

Since there's no real consequence for Dex rolls, other than falling prone, the only time that it is really worth making Dex checks is during a combat, when time is over the essence. Outside of combat, the PCs will eventually make it, and falling prone has no material effect if there isn't a monster to take advantage of your prone status.

There's no slip and slide rules for failing DEX trying to traverse a ice ramp?  Luge is deadly, as it's stripped down form called Skeleton.  Heck toboggan accidents aren't unheard of.  It sounds like there could be an environmental challenge independent of combat.  Sorta puzzled that it's being determined that it isn't.

EDIT: Read the scene, so sure half movement, and I'd call for the checks when it mattered or in a situation where the walker couldn't focus on their trudge (i.e. combat).  I do have a Turtle in one of my games who would definitely attempt to find some "high ground" enter shell, and have players hurl him downslope in an effort to bowl an enemy as a giant hockey puck (it's happened before).