Snowbot

Snow forecast notification service. Get Slack alerts when snow is in the forecast for your saved locations.

Data Sources

Snow forecast data comes from the NOAA HRRR (High-Resolution Rapid Refresh) model, made accessible as analysis-ready cloud-optimized data by dynamical.org and served via the Earthmover EDR API.

• Dataset: Snowbot HRRR on Earthmover Marketplace

How it works

                        ┌─────────────────┐
                        │  KV Store       │
                        │  (locations)    │
                        └────────┬────────┘
                                 │
                                 ▼
┌─────────────┐          ┌─────────────────┐          ┌─────────────────┐
│ Arraylake   │─webhook─▶│     Worker      │─────────▶│  Earthmover     │
│ (HRRR data) │          │                 │◀─────────│  EDR API        │
└─────────────┘          └────────┬────────┘          └─────────────────┘
                                  │
       ┌──────────────────────────┤
       │                          │ snow forecasted?
       ▼                          ▼
┌─────────────────┐     ┌─────────────────┐
│  Slack commands │     │  Slack alerts   │
│  /snowbot add   │     │                 │
│  /snowbot list  │     │                 │
└─────────────────┘     └─────────────────┘

1. Add locations via Slack: /snowbot add "Lake Tahoe" 39.0968 -120.0324
2. When HRRR forecast data updates, Arraylake sends a webhook to the worker
3. Worker queries Earthmover EDR for snow forecast at each location
4. If snow is forecasted, a Slack notification is sent

Slack commands

• /snowbot add "Name" lat lon - Add a location
• /snowbot list - List all locations
• /snowbot remove "Name" - Remove a location
• /snowbot help - Show help

Example Slack notification

🚨☃️🚨☃️🚨☃️🚨☃️🚨

🌨️ *SNOW ALERT!* 🌨️

❄️ *Tahoe City*
      🕒 Sun 1/19 2pm-8pm, Mon 1/20 6am-12pm

❄️ *Mammoth Lakes*
      🕒 Sun 1/19 4pm-11pm

🚨☃️🚨☃️🚨☃️🚨☃️🚨

Development

npm install
npm run dev

Deploy

npm run deploy

Setup

This app uses cloudflare for all infrastructure. Create a cloudflare account and install the wrangler CLI.

1. Initialize KV Store

Create a KV namespace to store location data:

# Create the KV namespace
npx wrangler kv namespace create SNOW_LOCATIONS

# Note the ID from the output, then update wrangler.json:
# "kv_namespaces": [
#   { "binding": "SNOW_LOCATIONS", "id": "<your-namespace-id>" }
# ]

For local development, create a preview namespace:

npx wrangler kv namespace create SNOW_LOCATIONS --preview

2. Create Slack App

1. Go to api.slack.com/apps and click Create New App
2. Choose From scratch, name it "Snowbot", and select your workspace

Configure Bot Token Scopes

1. Navigate to OAuth & Permissions in the sidebar
2. Under Scopes > Bot Token Scopes, add:
   • chat:write - Send messages
   • commands - Handle slash commands

Create Slash Command

1. Navigate to Slash Commands in the sidebar
2. Click Create New Command:
   • Command: /snowbot
   • Request URL: https://your-worker.workers.dev/api/slack/commands
   • Short Description: Manage snow alert locations
   • Usage Hint: [add|list|remove|help]

Install App to Workspace

1. Navigate to Install App in the sidebar
2. Click Install to Workspace and authorize
3. Copy the Bot User OAuth Token (starts with xoxb-)

Get Signing Secret

1. Navigate to Basic Information in the sidebar
2. Under App Credentials, copy the Signing Secret

Get Channel ID

1. In Slack, right-click the channel for snow alerts
2. Click View channel details
3. Copy the Channel ID at the bottom of the modal

3. Configure Secrets

Set these secrets via wrangler secret put <SECRET_NAME>:

wrangler secret put SLACK_BOT_TOKEN      # Bot token (xoxb-...)
wrangler secret put SLACK_DEFAULT_CHANNEL # Channel ID for alerts
wrangler secret put SLACK_SIGNING_SECRET  # Signing secret from app credentials
wrangler secret put FLUX_TOKEN            # Earthmover EDR API token
wrangler secret put WEBHOOK_SECRET        # Secret for webhook verification

Secret	Description
SLACK_BOT_TOKEN	Bot token for posting messages
SLACK_DEFAULT_CHANNEL	Channel ID for snow alerts
SLACK_SIGNING_SECRET	For verifying slash commands
FLUX_TOKEN	Earthmover EDR API token
WEBHOOK_SECRET	Shared secret for verifying incoming webhooks

4. Configure Webhook

When configuring the upstream webhook (e.g., Arraylake), include the X-Secret-Token header with the value of your WEBHOOK_SECRET:

POST /api/on-forecast-update
X-Secret-Token: <your-webhook-secret>