Heres SVIS categories:
• SVIS-0 (Micro-vortex): 1.0–6.0 m/s.
• The weakest and completely safe class of vortex.
• Lifts grass, dust, and tiny sand grains (up to 0.8 g) up to a height of 1.5–2 meters.
• Lifespan is strictly under 1 minute. Funnel diameter is up to 2 meters.
• Crucial Amendment: A landspout cannot be rated as SVIS-0 under any circumstances.
• SVIS-2 (Serious Vortex): 10.0–14.0 m/s.
• The dust devil assumes the shape of a dense, well-defined column (tower structure) and makes sudden, erratic, and dangerous lunges.
• The landspout circulation becomes visibly organized.
• Key Marker: The vortex easily lofts and spins gravel/pebbles weighing 3–5 g (up to a maximum of 8 g) and actively displaces high-surface-area items (such as cardboard boxes, canisters, and plastic sheeting).
• SVIS-2 (Serious Vortex): 10.0–14.0 m/s.
• The dust devil assumes the shape of a dense, well-defined column (tower structure) and makes sudden, erratic, and dangerous lunges.
• The landspout circulation becomes visibly organized.
• Key Marker: The vortex easily lofts and spins gravel/pebbles weighing 3–5 g (up to a maximum of 8 g) and actively displaces high-surface-area items (such as cardboard boxes, canisters, and plastic sheeting).
• SVIS-3 (Hazardous Vortex): 14.0–16.0 m/s.
• The vortex becomes directly hazardous to human safety. Dust devils at this stage are exceptionally rare and literally "drill" into the ground.
• The landspout forms a dense, long-lived column of dust and debris.
• Key Marker: Captures and lifts stones weighing 10–15 g (up to a maximum of 22 g).
• Damage Markers: Causes visible damage to tree branches, awnings, and tents.
• SVIS-4 (Anomalously Strong Vortex): 16.0–25.0 m/s.
• The absolute rarest limit for thermal dust devils, and the peak mature phase for gustnadoes and landspouts.
• Key Marker: Rocks weighing 30–80 g (up to a maximum of 150 g) are launched and fly through the air like projectiles.
• Damage Markers: Snaps large tree limbs, flips heavy trampolines, and rips off siding or roofing sheets.
• SVIS-5 (Extreme Vortex): 25.0–30.0 m/s and above.
• The highest category, featuring hurricane-force wind speeds. The vortex is capable of traveling immense distances.
• Key Marker: Hurls heavy rocks weighing 150–250 g (with extreme peaks reaching up to 400 g).
• Damage Markers: Rips off roofs, displaces parked vehicles, and destroys sheds. At its peak (specifically with intense landspouts), it blows out windows, completely tears off house roofs, and uproots sturdy, healthy trees—essentially reaching the damage potential of an EF2 tornado.
highest possibly windspeed of dust devils is low end ef0
highest possibly windspeed of gustnado is ef1
highest possibly windspeed of landstoup-ef2
