--- title: "Community early warning monitoring | Nexus Observatory" description: "National warnings often miss small valleys and villages, and arrive in ways not everyone receives. A community early warning system of rain and river gauges…" url: https://observatory.global/industries/communities/local-early-warning/ publisher: Nexus Observatory Inc. updated: 2026-11-02 --- [Nexus Observatory](https://observatory.global/) / [Communities](https://observatory.global/industries/communities/) / [Specialized fields](https://observatory.global/industries/communities/fields/) / **Community early warning** # Warnings that reach the last household. National warnings often miss small valleys and villages, and arrive in ways not everyone receives. A community early warning system of rain and river gauges, local thresholds, sirens and messages, linked to the national service, gives people the minutes they need to move. [Plan a deployment](https://observatory.global/contact/deployment/) How it works [Station Builder](https://observatory.global/studio/builder/) **Industry**: Communities **Measurements**: 4 **Sources cited**: 5 1. Communities · Community early warning Minutes that matter Flash floods in small valleys can rise in less than an hour, and national warnings often miss them or arrive in ways not everyone receives. The global disaster risk framework asks for early warning that is people-centred and reaches everyone. A community system gives people the minutes they need. 2. What is measured Rain upstream, rivers rising Rain gauges in the upper catchment and river gauges upstream of the community report every few minutes, faster when levels rise. Each gauge sits above past flood marks on a secure pole, with its own solar panel and battery, so it keeps reporting during the event. InstrumentsRain gauges · River level gauges 3. The base node Local thresholds, local alerts The node at the community centre applies thresholds agreed by the community and the national service. When rain or river crosses them, it sounds sirens, sends messages and radio announcements, and records every alert and every acknowledgement from focal points. 4. Radio and links Low-power radio, cellular and sirens Gauges reach the community gateway over a long-range, low-power link. The node exchanges alerts with the national service in the common alerting protocol over cellular, and community radio and sirens reach the households without phones, so nobody depends on a single channel. LinksLoRaWAN · Public cellular · VHF/UHF 5. How it works From a rain gauge to safe ground A storm stalls over the upper valley. Rain gauges report intense rainfall, then the river gauge climbs past its first threshold. The node sounds the sirens and sends messages; focal points check on elderly neighbours, families move to the school on the hill, and the national service sees the alert. 6. From order to operation · Order Scope with the community and the service The scope brings together the community, the local authority and the national warning service: the hazards, past floods, who must be warned, how and how fast. Nexus Observatory Inc. returns the gauge plan, thresholds approach, dissemination design, training and a price for building and for each year. [Plan a deployment](https://observatory.global/contact/deployment/) 7. From order to operation · Survey Map the risk together Crews walk the catchment with community members: flood marks and stories of past events, gauge sites safe from the floods they measure, gateway and siren positions, and the households hardest to reach. The risk map is drawn with the community. 8. From order to operation · Permits Land, radio and roles Land owners approve gauge sites, radio and siren use are licensed or registered, and the community agrees who receives alerts, who sounds sirens and who checks on vulnerable neighbours. The national service agrees how local alerts relate to its own warnings. 9. From order to operation · Build Build and test the chain Gauges, radios, the gateway, node, sirens and message service are configured and tested together as one chain, from a simulated rise to a siren and a message. Nodes are enrolled with their identities and community volunteers join the tests. Nothing ships until the whole kit has passed its tests together. [Open the Station Builder](https://observatory.global/studio/builder/) 10. From order to operation · Install Install with volunteers Crews and volunteers install gauges on secure poles above flood marks, the gateway and node at the community centre, and sirens where every household can hear them. Every part is photographed, and volunteers learn how to check each one. Crews follow the site safety plan throughout the work. 11. From order to operation · Commission Commission with a drill Each node proves its identity, gauges are checked against staff gauges and manual readings, and the community runs a full drill: alert, siren, messages, acknowledgements and movement to safe places. Response times are recorded and thresholds reviewed. Acceptance is recorded with the owner before handover. 12. From order to operation · Operate Warn and respond The community and the national service see rain and river levels live. Alerts go out by siren, message and radio when thresholds are crossed, focal points confirm that households have heard, and every event is recorded for the next review. 13. From order to operation · Maintain Drill every season Gauges are checked by volunteers before each rainy season, drills are repeated, thresholds are reviewed after every event, new volunteers are trained, and software updates arrive remotely in rings. Every change is kept with the system record. Maintenance history stays with each site for its whole life. [Book field services](https://observatory.global/contact/field-service/) 14. Data products For every household The community and local authority receive rain and river levels; every household receives alerts by siren, message and radio; focal points and the national service receive alert and acknowledgement records; the community and funders receive drill and event reviews, each tied to the place and time. [See the data products](https://observatory.global/data-products/) 15. Evidence People-centred, on record The system follows the four parts of the international early warning checklist and the people-centred approach of the global disaster risk framework. Rivers are gauged to hydrological practice, rain to the instrument guide, and alerts use the common alerting protocol. Every alert, drill and response is recorded. Drawn againstWMO-No. 1150 · Sendai Framework for Disaster Risk Reduction 2015-2030 · WMO-No. 168 · WMO-No. 8 · ITU-T X.1303 16. What you get Sensing as a Service Observation networks designed, installed, operated and maintained for a monthly fee: weather, hydromet, air, seismic and environmental stations, with data delivered under a licence. Delivered as managed service and data licence, for agencies, utilities, municipalities, insurers, agribusiness. Scale: Global, multi-site, per-site pricing. [Talk to sales](https://observatory.global/contact/sales-enquiry/) 17. Next step Plan community early warning with us Tell us the site, the measurements and the rules it answers to. We reply with a survey proposal, a design and a scope for community early warning. An engineer replies with a survey proposal and a scope, and the plan grows from one site to the network you need, at your pace. [Plan a deployment](https://observatory.global/contact/deployment/) [Open the Station Builder](https://observatory.global/studio/builder/) [Open the Studio](https://observatory.global/studio/) **01** The place and its hazards ## Where it runs, and what can go wrong. Operating contextThe global disaster risk framework calls for people-centred early warning, and the international checklist sets out its four parts: risk knowledge, monitoring, dissemination and response capability. Rivers are gauged to hydrological practice, rainfall to the instrument guide, and alerts are exchanged in the common alerting protocol so every channel can carry them. Hazards - Flash floods in small valleys with no national gauge - Warnings that never reach households without phones - Thresholds set far away without local knowledge - Gauges washed away in the floods they warn of - Volunteers who leave and take the skills with them **02** What must be measured ## What, where, how often, and under which rules. Each measurement names where it is taken, how often, and the public standard or regulation behind it. Numbers in the sources column open the cited source below. | Measurement | Where | Cadence | Sources | | --- | --- | --- | --- | | Rainfall | Gauges in the upper catchment | Every few minutes | 1 | | River level | Gauges upstream of the community | Every few minutes, faster when rising | 2 | | Alert dissemination and acknowledgement | Sirens, messages and focal points | Every alert | 34 | | Drills and response times | Community drills and real events | Each drill and event | 35 | **03** The observation stack ## From one base unit to a network. The same blocks at every scale: instruments and a base node, a site with its radio, a fleet run as one, and a network federated on the open protocol. 1. **01** Base unit A gauge: a rain or river sensor on a low-power radio with its own battery and solar panel. [Build a station →](https://observatory.global/studio/builder/) 2. **02** Site A community: gauges in the catchment, a gateway, a node at the community centre, sirens and a message service. [Plan a site →](https://observatory.global/contact/deployment/) 3. **03** Fleet Many communities in a basin linked, so an upstream rise warns those downstream. [Managed offers →](https://observatory.global/industries/communities/solutions/) 4. **04** Network Community systems exchange alerts with the national warning service in the common alerting protocol. [The open protocol →](https://observatory.global/protocol/) - **01** Water level gauge - **02** Compact weather station - **03** LPWAN endpoint - **04** LoRaWAN gateway - **05** Micro node (Nano) - **06** Cellular modem/router - **07** Solar array - **08** Pole Radio and links ### LoRaWAN Gauges in the catchment reach the community gateway over a long-range, low-power link. Radio and links ### Public cellular The node sends alerts and data to the national service and phones over cellular. Radio and links ### VHF and UHF radio Community radio and sirens reach households without phones. Edge computeThe node applies thresholds agreed with the community and the national service, raises alerts when rain or river crosses them, triggers sirens and messages, and records every alert and acknowledgement. PowerGauges run on small solar panels and batteries; the node and sirens have batteries that outlast a storm's power cut. **04** How it works ## From the instrument to the product. One observation's path, tier by tier, with the interface on every link and a bill of materials below; then how the one node grows to a site, a fleet and federated networks. Community early warning: data path – of 08 01 Instruments Measurement with sensor identity andcalibration 02 Field radio 03 Gateway 04 Node – Wrap in an observation envelope with timequality– Measure quality and uncertainty, attachquality flags– Buffer locally (store-and-forward when thelink drops) 05 Backhaul Commit with transactional outbox andpublish, delivered at least once 06 Site Consumer inbox deduplicates and applieseach record once into governed data 07 Data store Governed product through API, map orexport, correction-aware 08 Products CAP 1.2OGC SensorThings APIWMO WIS 2.0 09 Power and structure Supplies 12 V DC to the field equipment 01 Water level gauge SDI-12 · RS-485 · Ethernet 02 Compact weather station SDI-12 · RS-485 · Ethernet 03 LPWAN endpoint Analogue I/O · SDI-12 · RS-485 04 LoRaWAN gateway Ethernet · RF · GNSS antenna 05 Micro node (Nano) Ethernet · USB · Analogue I/O ·RS-485 · CAN 06 Cellular modem/router Ethernet · USB · RS-232 Site MQTT 5 with Sparkplug B Governed data store Versioned, correction-aware Rain and river levels Alerts by siren, message and radio Alert and acknowledgement records Drill and event reviews 07 Solar array RS-485 08 Pole SDI-12 SDI-12 LoRaWAN Ethernet Ethernet LTE/NR From the instrument to the published product: each band is a tier, each connector names its interface, and the numbers match the bill of materials. Hover or focus a block to trace its path; scroll or step to follow one observation. | Item | Equipment | Data ports | Protocols | Power in | | --- | --- | --- | --- | --- | | 01 | **Water level gauge** Radar, pressure or float gauge for river, lake, reservoir or tide level. | SDI-12RS-485Ethernet | SDI-12, Modbus, MQTT 5, OGC SensorThings API | 12 V DC | | 02 | **Compact weather station** All-in-one or compact station for temperature, humidity, pressure, wind and rain at a site. | SDI-12RS-485Ethernet | SDI-12, Modbus, MQTT 5, OGC SensorThings API | 12 V DC | | 03 | **LPWAN endpoint** Battery-powered endpoint on LoRaWAN, NB-IoT or LTE-M that carries one or more sensors. | Analogue I/OSDI-12RS-485 | LoRaWAN, OMA LwM2M, CoAP | Internal battery, Energy harvesting | | 04 | **LoRaWAN gateway** Multi-channel LoRaWAN gateway that forwards uplinks to a network server and schedules downlinks within duty limits. | EthernetRFGNSS antenna | LoRaWAN, MQTT 5 | PoE, 12 V DC | | 05 | **Micro node (Nano)** Single-board or module-class node for sensor sites, gateways and low-power deployments. | EthernetUSBAnalogue I/ORS-485CAN | MQTT 5, OMA LwM2M, CoAP | PoE, 12 V DC, USB PD | | 06 | **Cellular modem/router** LTE or NR modem or router that uses a public carrier or private network as backhaul. | EthernetUSBRS-232 | 3GPP E-UTRA air interface, 3GPP NR air interface, OMA LwM2M | 12 V DC, PoE | | 07 | **Solar array** PV modules with charge controller sized to the site's load and climate. | RS-485 | Modbus | — | | 08 | **Pole** Utility, street or dedicated pole with clamp positions. | — | — | — | How it scales 01 Instruments Arbitrary qualified sensors and instruments whosemeasurements are ingested with calibration, units,geometry, time, custody and uncertainty. ×n 02 Node The minimum useful deployable unit: server, ruggedappliance, radio node, sensor gateway, satelliteterminal, AI, scientific, vehicle or virtual node. Node Node agent 03 Site The minimum independently operable localgovernance and failure domain: one or more nodesplus local network, identity, policy, evidence,storage, products and operator surfaces. SITE Node Node Node ×n 04 Cluster An optional scale or specialisation domain forscheduling, shared storage, accelerators or datalocality. CLUSTER ×n 05 Fleet Coordinates plans, acknowledgements,convergence evidence, update campaigns andcorrection propagation across nodes and sites. FLEET Fleet controller ×n 06 Federation An exchange of products, capabilities, events orwork across approved, independently administeredtrust domains, using explicit trust, policy,data-locality, version and correction contracts. TRUST DOMAIN TRUST DOMAIN TRUST DOMAIN ×n Verifier Applications Data in the field Telemetry Control Data upstream Control Data upstream Control Exchange Evidence Events Exchange The smallest deployable unit is one node; the same unit is replicated to meet the demand. Nodes form a site, sites may form a cluster, sites and clusters are coordinated as a fleet, and fleets exchange across independently administered trust domains. Each plane is a separate channel with its own open binding. **Data in the field**: MQTT 5 with Sparkplug B; connectors for LoRaWAN, OPC UA and instrument buses. **Telemetry**: OpenTelemetry OTLP. **Control**: TLS 1.3 with mutual authentication; protobuf messages over gRPC or HTTP/2. **Data upstream**: At-least-once publication with repeat-safe keys over the control channel or NATS JetStream; QUIC MAY be used on lossy links. **Evidence**: DSSE-signed in-toto statements; SLSA provenance; SCITT transparency receipts. **Events**: Event envelopes mapped to CloudEvents 1.0; channels described in AsyncAPI 3. **Exchange**: OpenAPI 3.1; the OGC API family; SensorThings; STAC; WIS 2.0. **05** From order to operation ## Every step, from the first call to a running site. The same crew and the same record carry the work from scope to maintenance. 1. 01 Order Scope with the community and the service The scope brings together the community, the local authority and the national warning service: the hazards, past floods, who must be warned, how and how fast. Nexus Observatory Inc. returns the gauge plan, thresholds approach, dissemination design, training and a price for building and for each year. 35 2. 02 Survey Map the risk together Crews walk the catchment with community members: flood marks and stories of past events, gauge sites safe from the floods they measure, gateway and siren positions, and the households hardest to reach. The risk map is drawn with the community. 2 3. 03 Permits Land, radio and roles Land owners approve gauge sites, radio and siren use are licensed or registered, and the community agrees who receives alerts, who sounds sirens and who checks on vulnerable neighbours. The national service agrees how local alerts relate to its own warnings. 4. 04 Build Build and test the chain Gauges, radios, the gateway, node, sirens and message service are configured and tested together as one chain, from a simulated rise to a siren and a message. Nodes are enrolled with their identities and community volunteers join the tests. Nothing ships until the whole kit has passed its tests together. 5. 05 Install Install with volunteers Crews and volunteers install gauges on secure poles above flood marks, the gateway and node at the community centre, and sirens where every household can hear them. Every part is photographed, and volunteers learn how to check each one. Crews follow the site safety plan throughout the work. 6. 06 Commission Commission with a drill Each node proves its identity, gauges are checked against staff gauges and manual readings, and the community runs a full drill: alert, siren, messages, acknowledgements and movement to safe places. Response times are recorded and thresholds reviewed. Acceptance is recorded with the owner before handover. 3 7. 07 Operate Warn and respond The community and the national service see rain and river levels live. Alerts go out by siren, message and radio when thresholds are crossed, focal points confirm that households have heard, and every event is recorded for the next review. 4 8. 08 Maintain Drill every season Gauges are checked by volunteers before each rainy season, drills are repeated, thresholds are reviewed after every event, new volunteers are trained, and software updates arrive remotely in rings. Every change is kept with the system record. Maintenance history stays with each site for its whole life. 5 **06** Data products and integration ## What it delivers, to whom, and into which systems. Data products - **Rain and river levels** The community and the local authority - **Alerts by siren, message and radio** Every household - **Alert and acknowledgement records** Focal points and the national service - **Drill and event reviews** The community and funders Integration - **National warning service** Local alerts and data are exchanged in the common alerting protocol. - **Message services** Alerts reach phones through the channels people use. - **Local authority** Event records feed the authority's emergency planning. Exchanged through CAP 1.2, OGC SensorThings API, WMO WIS 2.0. **07** Questions buyers ask ## Before you scope it. Who sets the thresholds? The community and the national service together, reviewed after every event. What about households without phones? Sirens and community radio reach them, and focal points check on them. Will gauges survive a flood? They are sited above flood marks on secure poles. Does it replace national warnings? No. It adds local detail and reaches the last household. **08** Resources ## The sources behind this page. Public standards, regulations and guidance, cited where they apply. Each applies only where its jurisdiction or scope does. 1. **1** [WMO-No. 8: Guide to Instruments and Methods of Observation](https://library.wmo.int/) World Meteorological Organization 2. **2** [WMO-No. 168: Guide to Hydrological Practices](https://library.wmo.int/) World Meteorological Organization 3. **3** [WMO-No. 1150: Multi-hazard Early Warning Systems: A Checklist](https://library.wmo.int/) World Meteorological Organization · 2018 4. **4** [ITU-T X.1303: Common alerting protocol (CAP 1.2)](https://www.itu.int/) International Telecommunication Union 5. **5** [Sendai Framework for Disaster Risk Reduction 2015-2030](https://www.undrr.org/) United Nations Office for Disaster Risk Reduction · 2015 **09** Related ## Use cases and solutions. [Use case Street flood observatoryUltrasonic depth sensors on poles report street-level water depth as open data and alerts.The full use case →](https://observatory.global/use-cases/street-flood/) [Use case Low-cost stream gauge networkRadar or pressure level sensors with low-power radio and solar power, as a cheaper tier beside a national gauge network.The full use case →](https://observatory.global/use-cases/stream-gauge/) [Solution Sensing as a ServiceObservation networks designed, installed, operated and maintained for a monthly fee: weather, hydromet, air, seismic and environmental stations, with data delivered under a licence.Solutions for communities →](https://observatory.global/industries/communities/solutions/#sensing-service) [Solution Hydrometeorological and flood observing networksStream gauges, rain gauges, weather radar and automatic weather stations built to WMO practice, reporting through WIS 2.0 where the agency requires it.Solutions for communities →](https://observatory.global/industries/communities/solutions/#hydromet-networks) [Solution Operator and technician training on delivered systemsHands-on courses for customer staff on the systems they run; no public credentials are issued by the group.Solutions for communities →](https://observatory.global/industries/communities/solutions/#operator-training) **10** Communities: specialized fields ## Other fields of this industry. [Specialized field Community cellular and broadbandCellular and Wi-Fi networks a community owns and runs, on shared or community spectrum, with solar power and satellite or microwave backhaul where carriers do not build.The full field →](https://observatory.global/industries/communities/community-networks/) [Specialized field Community microgridsSolar, battery and backup generation for remote communities, monitored and run locally, with energy access measured to the international framework.The full field →](https://observatory.global/industries/communities/community-microgrids/) [Specialized field Small community water systemsWater quality, chlorine, tank levels and pumps in small community supplies, watched continuously so operators keep water safe and fix faults before taps run dry.The full field →](https://observatory.global/industries/communities/small-water-systems/) ### Bring us the site. Plan a deployment, configure a station, model it in the Studio or talk to sales. 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