1001 Smart Cities
🇧🇷 Rio de Janeiro

Alerta Rio: rain gauges, thresholds & favela sirens

🤖 AI-generated summary · ◆ 1 sourced claim · 🔎 Last verified

This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

1 sourced claim on this page, none individually verified yet — turn on “Sources in the text” to see each one.

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No rainfall reading sounds the sirens by itself; Civil Defence staff confirm the protocol first. The 164 sirens still cover the communities mapped in 2011, and two documented landslides since fell below the trigger.

Outcome🔄 Ongoing
Evidence🔬 Peer-reviewed
what does this mean?The strongest source behind this entry is an independent peer-reviewed or academic study. It grades who did the looking — not how well the project went. All four grades →
Run byFundação GEO-RIO & Defesa Civil Municipal, Prefeitura do Rio de Janeiro
Scale🏙️ City-wide

Part of 1001 Smart Cities — 1,167 documented projects · 🏙️ 12 more in Rio de Janeiro · 🌊 Flood resilience guide · 🌱 Environment projects

GEO-RIO built Alerta Rio after the 1996 Tijuca massif landslides: 33 telemetric stations report rainfall every five minutes, backed by two weather radars, and their readings set the city's alert stage. Since 2011, 164 sirens in 103 high-risk communities can order residents out to support points — but no reading sounds them by itself. When a gauge passes 55 mm in an hour, municipal Civil Defence staff confirm the protocol and trigger the sirens remotely from the city operations centre, where Alerta Rio's meteorologists sit. The siren network has not been extended since it was installed.

Live 📅 since 1996

📊 Impact

An independent evaluation of alerts issued 2010–2013 found the rainfall thresholds kept missed alerts low but generated a large number of false alarms, one zone's threshold probably being set too low (Calvello et al., International Journal of Disaster Risk Reduction, 2015).

🎓 Lesson

A warning system is only as wide as the map it was built on. Rio's sirens still match the 2011 risk survey, and two documented landslides — Morro da Babilônia in 2019, where two people died, and Rocinha in 2023 — happened below the trigger threshold.

🌱 EnvironmentFlood resilienceSensors & IoTSafety & securityOpen data

Sources

↗ Sistema Alerta Rio — Quem somos (GEO-RIO)Published 17 July 2026Operator. Created 25 September 1996 by Decree 15142, managed by Fundação GEO-RIO; network of 33 telemetric stations (25 rainfall-only, 5 with temperature/humidity, 2 full weather stations) transmitting every 5 minutes; radars at Sumaré and Mendanha.
↗ Centro de Operações e Resiliência — Rio em Estágio 2, balanço de 21/02 (2026)Published 21 February 2026Currency and mechanism, 21 February 2026: eight sirens sounded in four North Zone communities (Borel, Jamelão, Arrelia, Morro do Andaraí) after a gauge passed 55 mm in one hour, 'characterising the protocol'; all switched off at 20:30 as rain eased. Confirms a human stand-up and stand-down, not automatic actuation.
↗ Centro de Operações e Resiliência — 'Protocolo de acionamento em 24 horas não foi atingido' (2023)Published 28 August 2023The city's own account of a landslide in Rocinha, 27–28 August 2023, with no sirens sounded: 104.6 mm fell in 24 hours against a stated criterion of 150 mm in 24 hours. Note that sources differ on the 24-hour figure — RioOnWatch reports the landslide threshold was cut from 180 mm to 125 mm/24 h after a 1997 study by D'Orsi et al. — so no 24-hour number is asserted in the entry.
↗ Calvello, d'Orsi, Piciullo, Paes, Magalhães & Lacerda, 'The Rio de Janeiro early warning system for rainfall-induced landslides: analysis of performance for the years 2010–2013', International Journal of Disaster Risk Reduction 12 (2015) 3–15Published June 2015 archived copyPeer-reviewed performance evaluation and the basis of the impact field; co-authored by GEO-RIO's Ricardo d'Orsi, so not fully arm's-length, but published and independently reviewed. ScienceDirect returns 403 to automated fetches; abstract, citation and findings confirmed through two independent search paths including the lead author's publication list.
↗ RioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 1: a technical historyPublished 5 January 2020Origin in the 1996 Tijuca massif landslides (350 mm in 48 hours; 44 dead, 222 houses destroyed); first 30 rain gauges; radar and satellite added 1999; the community alert and alarm system (A2C2) as two levels — SMS to trained community leaders, then sirens; 194 support points and 165 sirens across 103 communities by March 2019; risk mapping not updated since 2013.
Show 3 more sourcesShow fewer
↗ RioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 2Published 13 January 2020The decision step, quoted: 'a preliminary consultation between Civil Defence and Geo-Rio leadership determines whether risk is sufficient before sounding an actual alarm'; a target of roughly two hours' warning; the 2019 Morro da Babilônia landslide that killed two with sirens not activated; and residents who stay put for fear of losing homes and possessions.
↗ Agência Brasil — 'Rio precisa ampliar sistema de alerta de deslizamentos' (April 2025), republished by Eu, Rio!Published 5 April 2025Carries the attributed audit figure: a 2022 Tribunal de Contas do Município report found roughly 400 Rio communities with neither sirens nor geological-geotechnical risk studies, mainly around the Pedra Branca massif in the west zone; and Rio 60ºC coordinator Miguel Vilela stating the system 'was launched in 2011, but they never installed sirens again'. The original agenciabrasil.ebc.com.br page currently serves an electoral-law placeholder to automated fetches, so the text was read through this republication; the TCM audit itself was not opened.
↗ Alerta Rio — download of rainfall dataPublished 17 July 2026Per-station rainfall series are published for download (records go back to 1997) and station metadata is mirrored on the city's data.rio portal. No licence or reuse terms are stated at the download point — downloadable, unlicensed, the same posture as Shanghai and Bangkok in this atlas.

📅 How old is the evidence?

Two clocks, kept apart: when this entry’s sources were published, and what has happened to its record in the atlas. Documented span: since 1996. 8 of 8 sources carry a publication date, from June 2015 to 17 July 2026.

When the sources were published

  1. ScienceDirect (Elsevier) · researchCalvello, d'Orsi, Piciullo, Paes, Magalhães & Lacerda, 'The Rio de Janeiro early warning system for rainfall-induced landslides: analysis of performance for the years 2010–2013', International Journal of Disaster Risk Reduction 12 (2015) 3–15
  2. RioOnWatch (Catalytic Communities) · ngoRioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 1: a technical history
  3. RioOnWatch (Catalytic Communities) · ngoRioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 2
  4. Centro de Operações e Resiliência do Rio (COR) · operatorCentro de Operações e Resiliência — 'Protocolo de acionamento em 24 horas não foi atingido' (2023)
  5. Agência Brasil (Empresa Brasil de Comunicação) · pressAgência Brasil — 'Rio precisa ampliar sistema de alerta de deslizamentos' (April 2025), republished by Eu, Rio!
  6. Centro de Operações e Resiliência do Rio (COR) · operatorCentro de Operações e Resiliência — Rio em Estágio 2, balanço de 21/02 (2026)
  7. Sistema Alerta Rio (Fundação GEO-RIO) · city governmentSistema Alerta Rio — Quem somos (GEO-RIO)
  8. Sistema Alerta Rio (Fundação GEO-RIO) · city governmentAlerta Rio — download of rainfall data

Every source, with links ↑

What happened to this record

  1. Sources last read
  2. Entered the record

Every revision, permanent →

Show your work What this page rests on and what it can’t tell you · all 1 claims with their sources · the forensic record

Evidence Passport · public beta 1 addressable claim, 8 source dossiers, one permanent baseline. The passport is unreviewed — an AI-assisted structural migration, not a human or expert endorsement. Every revision keeps a permanent copy under revision history.

Inspect the claims, one by one — verbatim text, sources and caveats for all 1

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-d713ca194f484a22 quantitative
An independent evaluation of alerts issued 2010–2013 found the rainfall thresholds kept missed alerts low but generated a large number of false alarms, one zone's threshold probably being set too low
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
No support note recorded
Caveat
The entry notes two documented landslides — Morro da Babilônia in 2019 and Rocinha in 2023 — happened below the trigger threshold, and the siren network has not been extended since 2011.

Sources carrying this claim

  1. Calvello, d'Orsi, Piciullo, Paes, Magalhães & Lacerda, 'The Rio de Janeiro early warning system for rainfall-induced landslides: analysis of performance for the years 2010–2013', International Journal of Disaster Risk Reduction 12 (2015) 3–15
Forensic record — source dossiers, gaps, hashes and the exact revision this page renders

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-20-source-dates effective 2026-07-26 · created 2026-08-20

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:d11947de19522a23e6933540744365d4b5fabfbc1e42bdb07a9013f00fa213e0
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
1
of 1 claims mapped
8
source dossiers
7
publication dates recorded
1
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Fundação GEO-RIO & Defesa Civil Municipal, Prefeitura do Rio de Janeiro
Actor types
city-government
Funding model
public
Funding description
Not recorded
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

8 source dossiers

Sistema Alerta Rio — Quem somos (GEO-RIO) sistema-alerta-rio.com.br · background

Open original source ↗

Stable source ID
src-0633ba129b03d684
Publisher
Name not classified · sistema-alerta-rio.com.br
Type / language
web-page · language not classified
Published
2026-07-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Operator. Created 25 September 1996 by Decree 15142, managed by Fundação GEO-RIO; network of 33 telemetric stations (25 rainfall-only, 5 with temperature/humidity, 2 full weather stations) transmitting every 5 minutes; radars at Sumaré and Mendanha.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Centro de Operações e Resiliência — Rio em Estágio 2, balanço de 21/02 (2026) cor.rio · background

Open original source ↗

Stable source ID
src-85d1eb1c50c71c44
Publisher
Name not classified · cor.rio
Type / language
web-page · language not classified
Published
2026-02-21
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Currency and mechanism, 21 February 2026: eight sirens sounded in four North Zone communities (Borel, Jamelão, Arrelia, Morro do Andaraí) after a gauge passed 55 mm in one hour, 'characterising the protocol'; all switched off at 20:30 as rain eased. Confirms a human stand-up and stand-down, not automatic actuation.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Centro de Operações e Resiliência — 'Protocolo de acionamento em 24 horas não foi atingido' (2023) cor.rio · background

Open original source ↗

Stable source ID
src-3ca01e401d4a5a3a
Publisher
Name not classified · cor.rio
Type / language
web-page · language not classified
Published
2023-08-28
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The city's own account of a landslide in Rocinha, 27–28 August 2023, with no sirens sounded: 104.6 mm fell in 24 hours against a stated criterion of 150 mm in 24 hours. Note that sources differ on the 24-hour figure — RioOnWatch reports the landslide threshold was cut from 180 mm to 125 mm/24 h after a 1997 study by D'Orsi et al. — so no 24-hour number is asserted in the entry.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Calvello, d'Orsi, Piciullo, Paes, Magalhães & Lacerda, 'The Rio de Janeiro early warning system for rainfall-induced landslides: analysis of performance for the years 2010–2013', International Journal of Disaster Risk Reduction 12 (2015) 3–15 sciencedirect.com · 1 linked claim

Open original source ↗

Stable source ID
src-e77d73f75507b84d
Publisher
Name not classified · sciencedirect.com
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
Open archived copy ↗ · 2024-04-15
Content hash
No captured content hash
Locator
Open the recorded source note

Peer-reviewed performance evaluation and the basis of the impact field; co-authored by GEO-RIO's Ricardo d'Orsi, so not fully arm's-length, but published and independently reviewed. ScienceDirect returns 403 to automated fetches; abstract, citation and findings confirmed through two independent search paths including the lead author's publication list.

Descriptive only — not page/paragraph exact
Claims linked
RioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 1: a technical history rioonwatch.org.br · background

Open original source ↗

Stable source ID
src-bfaa7f6d1565714e
Publisher
Name not classified · rioonwatch.org.br
Type / language
web-page · language not classified
Published
2020-01-05
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Origin in the 1996 Tijuca massif landslides (350 mm in 48 hours; 44 dead, 222 houses destroyed); first 30 rain gauges; radar and satellite added 1999; the community alert and alarm system (A2C2) as two levels — SMS to trained community leaders, then sirens; 194 support points and 165 sirens across 103 communities by March 2019; risk mapping not updated since 2013.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
RioOnWatch — Rio de Janeiro's landslide mitigation tactics, part 2 rioonwatch.org.br · background

Open original source ↗

Stable source ID
src-a68279b4d4b92f17
Publisher
Name not classified · rioonwatch.org.br
Type / language
web-page · language not classified
Published
2020-01-13
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The decision step, quoted: 'a preliminary consultation between Civil Defence and Geo-Rio leadership determines whether risk is sufficient before sounding an actual alarm'; a target of roughly two hours' warning; the 2019 Morro da Babilônia landslide that killed two with sirens not activated; and residents who stay put for fear of losing homes and possessions.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Agência Brasil — 'Rio precisa ampliar sistema de alerta de deslizamentos' (April 2025), republished by Eu, Rio! eurio.com.br · background

Open original source ↗

Stable source ID
src-1a46a0486119fee6
Publisher
Name not classified · eurio.com.br
Type / language
web-page · language not classified
Published
2025-04-05
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Carries the attributed audit figure: a 2022 Tribunal de Contas do Município report found roughly 400 Rio communities with neither sirens nor geological-geotechnical risk studies, mainly around the Pedra Branca massif in the west zone; and Rio 60ºC coordinator Miguel Vilela stating the system 'was launched in 2011, but they never installed sirens again'. The original agenciabrasil.ebc.com.br page currently serves an electoral-law placeholder to automated fetches, so the text was read through this republication; the TCM audit itself was not opened.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Alerta Rio — download of rainfall data sistema-alerta-rio.com.br · background

Open original source ↗

Stable source ID
src-ba5d8b27a90982cc
Publisher
Name not classified · sistema-alerta-rio.com.br
Type / language
web-page · language not classified
Published
2026-07-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Per-station rainfall series are published for download (records go back to 1997) and station metadata is mirrored on the city's data.rio portal. No licence or reuse terms are stated at the download point — downloadable, unlicensed, the same posture as Shanghai and Bangkok in this atlas.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Known limits of this passport
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.

Continue exploring

Compare this project

🇧🇷 Rio's Heat Levels: a five-tier extreme-heat protocol · Rio de Janeiro The heat levels are computed from Alerta Rio's official station — the one the city's own favela sensors read almost 10°C hotter than. 🇧🇷 Rio Operations Center (COR) · Rio de Janeiro Alerta Rio's meteorologists sit in the COR, and Civil Defence triggers the 164 sirens from there once a gauge passes 55 mm in an hour. 🇯🇵 Tsunami-Alert Automatic Tide Gate Closure · Osaka Osaka's gates shut themselves on a tsunami warning; Rio's sirens wait for Civil Defence to confirm the protocol before anyone hears them.

Explore the wider context

📟 A Reading Is Not a Decision📖 Flood early-warning system📖 Automated speed enforcement (speed cameras)📖 Integrated command and control centre (ICCC)
📎 Cite this project

1001 Smart Cities (2026). “Alerta Rio: rain gauges, thresholds & favela sirens” — Rio de Janeiro, Brazil. The Smart City Atlas. https://1001smartcities.org/projects/rio-alerta-rio/ (last verified 2026-07-26). Data: CC BY 4.0.

The underlying data is free to reuse with attribution — see the open data page.

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