Flood and Severe Weather Response

Floods, hurricanes, tornadoes, and severe winter storms each create different communication challenges. This page covers how mesh networks support response operations across severe weather scenarios.

Flood-specific considerations

Equipment waterproofing

Water is the primary hardware risk in flood scenarios. All field equipment should be in IP65+ rated enclosures or waterproof cases during flood response. For personal nodes:

• T1000-E: IP65-rated (per Seeed) - resists splashing and spray, but keep it out of standing water and immersion; IP65 is not rated for sustained submersion
• T-Echo: Not rated; put in a small zip-lock bag or simple waterproof case during rain operations
• Heltec V3/V4: Not rated; laptop bag or waterproof case required

Elevated deployment

Flood scenarios require nodes to be deployed well above the anticipated flood level. Ground-level repeaters in flood zones should be identified and planned for relocation to higher sites during flood events. Maintain a pre-planned list of above-flood-level backup sites for your mesh repeaters.

Hurricane/tropical storm preparation

Before a storm:

1. Secure or remove antenna masts from exposed locations - in high wind an unsecured mast or vertical can become a projectile or bend the SMA connector (the "5 dBi fiberglass vertical at 100 mph" figure is illustrative, not a measured spec)
2. Verify all solar-powered nodes have full battery charge before the storm
3. Activate the community mesh "storm watch" channel if your network has one
4. Distribute personal nodes to participants who don't have them
5. Confirm that key participants know the channel name and PSK without needing to look it up

During a storm:

• Minimize transmissions to reduce battery drain on nodes that may not see sun for days
• Use standard welfare check format to efficiently survey neighborhood status
• At 915 MHz, rain has negligible direct effect on the signal - rain attenuation only becomes significant in microwave bands above roughly 5-10 GHz (ITU-R P.838). Range loss in storms is dominated by wet foliage, higher humidity, and lower antenna positions, not the rain itself.

Winter storm and extended power outage

Multi-day ice storms and blizzards create extended power outages with dangerous conditions that prevent physical access. Key preparations:

• Battery sizing: Solar panels under snow produce no power. Ensure battery autonomy covers the longest expected outage without sun. As a planning example, in northern latitudes this can be 5 - 10 days during winter storms; size from your actual load and local insolation rather than treating that range as a fixed figure.
• Panel tilt: A steep panel angle (60 - 70° from horizontal) helps snow slide off and improves low winter-sun capture when panels are clear. Optimal winter tilt is roughly your latitude plus 15°.
• Cold battery performance: LiFePO4 capacity drops in the cold (about 60% of its 15°C capacity near -20°C). More importantly, never charge any lithium battery, including LiFePO4, below 0°C (32°F) - sub-freezing charging causes lithium plating and permanent damage. A BMS that blocks cold charging protects the pack; it does not enable charging below freezing. Use a self-heating battery or a low-temperature charge cutoff, and size the pack 20 - 30% larger for mild cold, up to ~40-50% larger near -20°C.
• Personal node operation: Keep personal nodes in warm pockets - battery capacity drops sharply in cold. Charge from vehicle power banks if grid is out (and not while the battery is below freezing).

Net operating procedures for severe weather

Welfare check format

STATUS REPORT
Node: [NODE-NAME or callsign]
Location: [neighborhood or cross street]
Status: [OK / NEED-ASSIST / EMERGENCY]
Injuries: [none / n minor / n serious]
Power: [on / out]
Notes: [any relevant info]

Priority message tags

Pre-establish a priority system for your community net:

• [ROUTINE]: General updates, non-urgent status
• [PRIORITY]: Important but not life-threatening (road closed, shelter open)
• [EMERGENCY]: Immediate life-safety issue requiring response

All participants should know that [EMERGENCY] messages trigger immediate net control response and that they should not use the tag for non-life-safety situations. Remember that mesh is best-effort: sending an [EMERGENCY] message does not guarantee it was delivered or seen. For any true life-safety emergency, attempt 911/voice first, and require an explicit acknowledgment before assuming a mesh [EMERGENCY] message was received.