Powder Snow

Powder snow is a block currently available only in the creative inventory. It is part of the upcoming 1.17 Caves and Cliffs update for the Java and Bedrock editions. Currently it is only present in Bedrock edition development versions.

Obtaining
Powder snow is currently only available from the Creative inventory via Experimental Gameplay.

Breaking
Powder snow does not drop anything when mined, even with Silk Touch, and tools do not speed up mining.

Usage
Entities fall through powder snow without taking fall damage and move much slower in it, similar to cobwebs. Despite being a full block, it does not cause suffocation damage. If a player's head is within the block, they will see a frosty vignette decorated with snowflakes.

Powder snow can be used to make technical farms, instead of water.

Mobs or players wearing leather boots do not fall through powder snow and will act like scaffolding when the player sneak or crouch while on the block and jump while inside of the block.

Trivia

 * "Snowier Snow" was announced to be part of the Mountains biome in the biome vote at MINECON Live 2019. This was strongly implied during Minecraft Live 2020 to be a separate feature from Powder Snow. However, when "Snowier Snow" was first mentioned in the 2019 biome vote video, a block is seen functioning similarly to Powder Snow. Powder Snow is often referred to as "Snowier Snow" by the community, and it's possible that Powder Snow is one of multiple parts of the promised "Snowier Snow" feature, with the other part possibly being a parity feature such as Snowlogging, or some other as-yet unknown feature.