Snowflakes
Classification
(aka resistance to structural change)
NOTE: This classification applies to specific transformational depths (from seed boundaries). SOS Classifications cannot be compared across different depths.
So a “resilient structure” classification for astronomical bodies cannot be compared to one for human immunity series.
Though intricate, snowflakes are transient crystallizations highly sensitive to environmental conditions. Their structure is instantly destroyed upon melting or touch.
Type of boundary
Others
Snowflakes are technically crystals
Understanding the boundary
Environmental context
Snowflakes form in cold atmospheric layers when water vapor condenses directly into ice crystals. They are found in clouds and in precipitation during sub-zero conditions. Their formation depends on temperature, humidity, and air turbulence, making them a transient feature of the hydrological and atmospheric system.
Mechanism for determining boundary
A snowflake’s boundary is defined by the crystalline lattice of frozen water molecules, typically forming a hexagonal geometry. Like most physical boundaries, the snowflake technically ends when the density of this lattice goes to zero.
The boundary is physically closed, formed by the aggregation of ice molecules into a singular unit. Once the flake melts or sublimates, the boundary ceases to exist.
Associated boundaries: higher scales
(not exhaustive)
- Atmospheric Weather Systems: Snowflakes are products of cloud systems, condensation processes, and temperature gradients in the troposphere.
- Hydrological Cycle: Part of the broader water cycle — transitioning between vapor, liquid, and solid phases.
Associated boundaries: lower scales
(not exhaustive)
- Ice Crystals / Crystal Facets: Each snowflake is composed of substructures (arms, plates, dendrites) formed from tightly ordered ice crystals.
- Water Molecules (H₂O): Fundamental molecular units involved in hydrogen bonding and freezing.
Understanding interactions
Most commonly interacting boundaries
at similar scales (not exhaustive)
1. Water Vapor in the Air
- Role: Supply material that freezes into ice crystals.
- Timing: Continuous at cold temperatures; peaks when humidity is high.
- Effect: High humidity and sub-freezing temperatures allow snowflake formation; dry air can halt growth.
2. Dust or Pollen Particles (Nuclei for Ice Formation)
- Role: Provide a surface for water vapor to deposit and freeze.
- Timing: Whenever ice nucleation temperatures (around –5°C to –10°C) are reached.
- Effect: Without a nucleus, water vapor stays gaseous; with one, a dendritic crystal can begin.
3. Temperature and Supersaturation Levels
- Role: Dictate the snowflake’s shape (plates, needles, dendrites).
- Timing: Varies within clouds—slight temperature changes shift forms.
- Effect: Warmer clouds produce simple plates, colder yield complex dendrites.
4. Air Currents and Turbulence
- Role: Move snowflakes through regions of varying humidity and temperature.
- Timing: Continuous within clouds and during descent to the ground.
- Effect: Creates layered growth as the snowflake moves, often leading to intricate branching.
Mechanism for common interactions
(not exhaustive)
1. Deposition (Vapor-to-Ice Transition)
- How It Starts: Air becomes supersaturated—contains more water vapor than it can hold at a given temperature.
- What Flows: Vapor molecules collide with an ice nucleus and stick, freezing in place.
- Effect: Base hexagonal plate forms; further deposition builds branches from each face.
2. Crystal Habit Formation (Shape Determination)
- How It Starts: Local temperature and humidity conditions around the flake vary.
- What Flows: Water molecules attach preferentially to certain edges.
- Effect: At –15°C and high humidity, complex dendrites grow; at –2°C, simpler plates form.
3. Aggregation (Snowflake Clumping)
- How It Starts: Falling flakes collide and stick gently in supersaturated, calm air.
- What Flows: Micro-bridges of ice or liquid water gluing flakes together.
- Effect: Forms larger snowflakes or snow pellets, affecting how fluffy or wet the snow is at ground level.
4. Sublimation and Melting (Loss of Ice to Vapor or Liquid)
- How It Starts: Snowflake enters a warmer or drier layer during descent.
- What Flows: Ice molecules revert to vapor (sublimation) or melt into liquid.
- Effect: Flake shrinks or changes shape—sometimes leaving only a small fragment or turning into a droplet before reaching the ground.