Waterweave

"The aarakocra make a habit of roosting in the most inhospitable places. Set well above the clouds, Rocky Roost is dry and cold. Neither rain nor snow falls upon frozen stone. If water does not come from the sky, and the ground is frozen, how do they find water to drink? The answer is their unique art: waterweaves. These intricately woven hoops are dipped into the clouds and hauled up, covered in ice crystals. Where they get the heat to melt the ice into water is another subject entirely."
Professor Dreyr giving a practical example of deposition in his lecture on phase changes

Utility

Aarakocra tow waterweaves below them as they fly over clouds. The waterweaves collect ice from the clouds while allowing the aarakocra to stay out of their icy grasp.
Feathers and beads are often added to signal when the waterweave is full of ice. They are specially cut to whistle and jangle while the wind blows by, but when ice accumulates they grow silent.

Manufacturing

The best waterweaves are considered works of art, and the construction of a new waterweave is always taken seriously by the craftsman regardless of talent. Each waterweave is handcrafted from a variety of materials. Wicker rings are usually crafted from rockvine, though more elegant rings may be constructed from exotic woods or even light metals such as mithral. The cording typically consists of leather or fibrous rope, and the jangles consist of decorative stones, feathers, shells, and horn.

Access & Availability

The waterweave is widely used in aarakocran nursery settlements, which are all on high points above the clouds. Creating and using a waterweave is part of a fledgling aarakocra's right of passage into adulthood. Adults in such settlements use waterweaves on a daily basis.

Discovery

The idea behind the waterweave originated with the aarakocra Qilhaal, who noticed that ice stuck to his cold pack when passing through the clouds. He conclude that ice would be easier to carry than water, and started lowering ropes into clouds and pulling them back up covered in ice so he could melt the crystals for drinking water later. Later improvements where made, incorporating more in loose tangles to get more icing area.
This concept was taken to its current form by Runhi, who wove her ropes around a wicker hoop instead of leaving them in a loose tangle.