Organize Your Block
A cascading notification system for your block. Each person contacts two. The whole neighborhood knows in minutes. Works when phones, internet, and power are all down.
The problem
During Hurricane Maria, 95% of cell towers in Puerto Rico went offline. During the 2021 Texas winter storm, cell networks were congested within hours of the power grid failing. After the 2023 Maui wildfire, cell service was unavailable across much of the affected area. The pattern repeats after every major disaster: the communication system you rely on daily stops working at the exact moment you need it.
A communication tree solves this by creating a cascading notification system that degrades gracefully. It starts with phone calls when they work. When phones fail, it falls back to the oldest communication technology available: walking to the door and knocking.
Setup time: about three hours total (mapping, assigning contacts, printing copies, running a first test). Maintenance: 15 minutes per quarter for a test run.
The structure
One person receives or notices information that the whole block needs to know: a gas leak, an evacuation order, a neighbor who needs help, a boil-water advisory. That person contacts two or three pre-assigned neighbors. Each of those contacts two or three more. Within minutes, the entire block has been reached.
The key design principle is redundancy. No single person is responsible for contacting more than three others. If one person is not home or cannot pass the message, the tree routes around them because multiple paths exist to every household. This is what makes it different from one person trying to contact everyone.
Example: 15-household block
Coordinator contacts 3 neighbors. Each of those contacts 2 more. Each of those contacts 2 more. Result: 1 + 3 + 6 + 5 = 15 households reached in four tiers. Maximum time if walking door-to-door: about 20 minutes. Maximum phone calls by any one person: 3.
The coordinator does not need to be a leader, organizer, or even particularly social. They need to be reliably home and willing to make three phone calls or knock on three doors.
Graceful degradation
Tier 1: Phone call or text
The default method when infrastructure is working. Call first, text if no answer. Move to Tier 2 if you get no response within 10 minutes. During a power outage without cell service, skip directly to Tier 2.
Tier 2: Walk to the door
The backup that always works. Walk to your assigned neighbors' doors. Knock, deliver the message, confirm they will pass it along. This is why physical proximity determines the tree structure, not friendship or social connection.
Tier 3: Backup channel
Optional but valuable. FRS/GMRS radios ($25 to $50 per pair, no license required for FRS) allow voice communication across a block or neighborhood when both phones and walking are impractical (nighttime, severe weather, flooding between houses). If anyone on the block has a ham radio license, a handheld VHF radio can reach much further. See our communications guide.
Design for failure
1. Assign by proximity, not preference. Your assigned contacts should be the households physically closest to you. You need to be able to walk to their door in under two minutes. Social relationships are a bonus, not the organizing principle.
2. Limit each person to 2 or 3 contacts. More than three and people forget or skip someone under stress. Two is ideal. Three is the maximum.
3. Build in redundancy. Each household should be contactable by at least two people in the tree. If one branch fails, the other still delivers the message. Draw the tree so every household has a primary contact and a backup contact.
4. Print it on paper. Every household gets a laminated card or a sheet in a zip bag posted on the refrigerator. Paper does not need power, signal, or a password. The card should show the full tree structure, every name, every address, and every phone number.
5. Designate an alternate coordinator. The coordinator is usually the person who organized the tree. The alternate steps in when the coordinator is traveling, at work, or unavailable. Without an alternate, the tree has a single point of failure at its root.
It only works if you test it
An untested communication tree is a list of phone numbers, not a system. Run a test once per quarter. The test is simple: the coordinator sends a short, obviously non-emergency message through the tree ("This is a test of the block communication tree. Please pass along and reply to [coordinator] when you receive it."). Time how long it takes to reach the last person.
After the test, note what happened. Who was home? Who passed the message quickly? Where did the chain stall? Did anyone's contact information change? Update the tree and redistribute the printed copies.
The quarterly test also serves as maintenance. Phone numbers change. People move. New households arrive. A tree that is not updated eventually contacts people who no longer live there. Fifteen minutes per quarter keeps it current.
Related guides
Before the next one
A communication tree is the neighborhood-level version of your family communication plan. If your household does not have one yet, start there. See our guide to building a family communication plan that works when phones are down.
Communications preparednessSources