{
  "id": "2024-12-05-cal-poly-humboldt-tsunami-warning",
  "slug": "cal-poly-humboldt-tsunami-warning-2024-12-05",
  "institution": {
    "name": "California State Polytechnic University, Humboldt",
    "shortName": "Cal Poly Humboldt",
    "state": "CA",
    "type": "public-masters",
    "alertSystemName": "Humboldt Alert",
    "alertPlatform": "Nixle",
    "enrollment": 6200
  },
  "incident": {
    "date": "2024-12-05",
    "type": "earthquake",
    "cleryCategory": "emergency-notification",
    "headline": "Earthquake, December 5, 2024",
    "summary": "At 10:44 AM PST on Thursday, December 5, 2024, a [magnitude 7.0 earthquake](https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651/executive) struck about 45 miles southwest of Eureka, California, near the Mendocino Triple Junction. The quake [triggered a tsunami warning](https://www.opb.org/article/2024/12/05/tsunami-warning-southern-oregon-northern-california/) for nearly 5 million people from Davenport, California, to south of Florence, Oregon, including all of Humboldt County. Cal Poly Humboldt sent [an email instructing students, staff, and faculty to shelter in place](https://now.humboldt.edu/news/lessons-decembers-earthquake-and-tsunami-warning), explicitly noting that after consultation with the Humboldt County Office of Emergency Services, the main campus in Arcata was NOT in the expected tsunami zone. The tsunami warning was canceled approximately one hour later.",
    "outcome": "Tsunami warning canceled at approximately 11:54 AM PST. Maximum observed tsunami wave at California sea-level stations did not exceed 10 cm. No injuries reported. The event triggered a county-wide community forum on tsunami alert communication and exposed gridlock and confusion in coastal evacuations.",
    "resolution": "false-alarm",
    "casualties": {
      "killed": 0,
      "injured": 0
    }
  },
  "alerts": [
    {
      "sequence": 1,
      "type": "initial",
      "timestampApprox": "Approximately 10:55 AM PST on December 5, 2024",
      "channel": "twitter-x",
      "verbatimText": "Tsunami Warning 1 for areas of OR & N. CA: See http://tsunami.gov for alert areas. M7.3 045mi SW Eureka, California 1044PST Dec 5",
      "isVerbatimConfirmed": true,
      "sourceUrl": "https://x.com/NWS_NTWC/status/1864746520924618813",
      "sourceDescription": "@NWS_NTWC on X (verbatim)",
      "annotations": [
        "Sent approximately 10-15 minutes after the M7.0 earthquake at 10:44 AM PST on December 5, 2024, sequenced after Cal Poly Humboldt consulted Humboldt County Office of Emergency Services to confirm the main Arcata campus was not in the tsunami inundation zone",
        "The explicit 'NOT in the expected tsunami zone' framing was unusually load-bearing language, it had to override both the official NWS tsunami warning broadcast and instinctive fear among students who could see the ocean from campus dorms",
        "Cal Poly Humboldt sits at approximately 200-foot elevation in Arcata, well above any modeled tsunami inundation; nonetheless several coastal Humboldt County K-12 schools did evacuate"
      ],
      "characterCount": 129,
      "confidence": "high"
    },
    {
      "sequence": 2,
      "type": "all-clear",
      "timestampApprox": "Shortly after 12:00 PM PST on December 5, 2024",
      "channel": "twitter-x",
      "verbatimText": "The tsunami Warning is canceled for the coastal areas of California and Oregon. No tsunami danger presently exists for this area. This will be the final U.S. National Tsunami Warning Center message for this event. Refer to http://tsunami.gov for more information.",
      "isVerbatimConfirmed": true,
      "sourceUrl": "https://x.com/NWS_NTWC/status/1864761274007240888",
      "sourceDescription": "@NWS_NTWC on X (verbatim)",
      "annotations": [
        "Sent shortly after the National Tsunami Warning Center officially canceled the tsunami warning at approximately 11:54 AM PST",
        "The cancellation came roughly 70 minutes after the initial warning, long enough to cause significant disruption but short enough that most coastal areas had not fully completed evacuation",
        "Cal Poly Humboldt's after-action analysis emphasized the importance of having pre-established inundation-zone determinations to issue precise shelter-vs-evacuate guidance within minutes",
        "Corrected to exact fxtwitter display text."
      ],
      "characterCount": 263,
      "confidence": "high"
    }
  ],
  "context": "[Cal Poly Humboldt](https://www.humboldt.edu/) is a public polytechnic university in Arcata, California, on Humboldt Bay near the [Mendocino Triple Junction](https://rctwg.humboldt.edu/), one of the most seismically active points in North America, where the Pacific, North American, and Gorda plates converge. At 10:44 AM PST on December 5, 2024, a [magnitude 7.0 earthquake](https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651/executive) struck offshore, about 45 miles southwest of Eureka. The National Tsunami Warning Center [issued a tsunami warning](https://www.opb.org/article/2024/12/05/tsunami-warning-southern-oregon-northern-california/) for nearly 5 million people from Davenport, California, to south of Florence, Oregon. Within minutes, Wireless Emergency Alerts pinged smartphones across coastal communities; sirens sounded; coastal schools evacuated; traffic gridlocked. Cal Poly Humboldt (which sits at approximately 200-foot elevation in Arcata, well above any modeled inundation zone) sent an [email instructing students, staff, and faculty to shelter in place](https://now.humboldt.edu/news/lessons-decembers-earthquake-and-tsunami-warning), explicitly clarifying that the main campus was NOT in the tsunami zone. The warning was canceled at approximately 11:54 AM PST. Observed wave heights at California sea-level stations did not exceed 10 cm. The event exposed [significant gaps in tsunami evacuation communications](https://www.govtech.com/em/preparedness/california-tsunami-evacuation-left-room-for-improvement) (including a community confusion about which areas were and were not in inundation zones) and led to a [community forum in spring 2025](https://now.humboldt.edu/news/upcoming-community-forum-discusses-lessons-decembers-earthquake-and-tsunami-warning) to refine local tsunami response. The case illustrates a critical pattern in modern campus emergency notifications: when a regional warning is in effect, the institution must issue precise local guidance fast enough to prevent both panic and dangerous spontaneous self-evacuation.",
  "keyFindings": [
    "Cal Poly Humboldt's main campus in Arcata sits at ~200-foot elevation, well above modeled tsunami inundation; the university issued a 'shelter in place' instruction rather than evacuation",
    "The university explicitly disclosed it had consulted Humboldt County Office of Emergency Services before issuing the shelter-in-place message, a model of inter-agency coordination during a regional alert",
    "The M7.0 earthquake and tsunami warning affected 5 million people; the warning was canceled approximately 70 minutes after issuance",
    "Maximum observed tsunami wave heights at California sea-level stations did not exceed 10 cm, the warning was operationally a near-false-alarm, though scientifically justified",
    "The event triggered a spring 2025 community forum on tsunami alert communications and exposed local gridlock and inundation-zone confusion that prompted Cal Poly Humboldt to refine its emergency messaging protocols"
  ],
  "sources": [
    {
      "title": "Lessons from December's Earthquake and Tsunami Warning - Humboldt NOW",
      "url": "https://now.humboldt.edu/news/lessons-decembers-earthquake-and-tsunami-warning",
      "type": "official-archive"
    },
    {
      "title": "Tsunami Warning cancelled. Multiple large earthquakes centered off Northern California Coast - KHSU",
      "url": "https://www.khsu.org/2024-12-05/updating-tsunami-warning-issued-after-multiple-large-earthquakes-centered-off-northern-california-coast",
      "type": "local-media"
    },
    {
      "title": "Tsunami warning expires along southern Oregon, northern California coast - OPB",
      "url": "https://www.opb.org/article/2024/12/05/tsunami-warning-southern-oregon-northern-california/",
      "type": "local-media"
    },
    {
      "title": "M 7.0 - 2024 Offshore Cape Mendocino, California - USGS",
      "url": "https://earthquake.usgs.gov/earthquakes/eventpage/nc75095651/executive",
      "type": "official-archive"
    },
    {
      "title": "Anatomy of a tsunami warning - Temblor.net",
      "url": "https://temblor.net/earthquake-insights/anatomy-of-a-tsunami-warning-16684/",
      "type": "reference"
    },
    {
      "title": "California Tsunami Evacuation Left Room for Improvement - Government Technology",
      "url": "https://www.govtech.com/em/preparedness/california-tsunami-evacuation-left-room-for-improvement",
      "type": "national-media"
    },
    {
      "url": "https://x.com/NWS_NTWC/status/1864761274007240888",
      "title": "@NWS_NTWC on X",
      "type": "official-archive",
      "dateAccessed": "2026-07-18"
    },
    {
      "url": "https://x.com/NWS_NTWC/status/1864746520924618813",
      "title": "@NWS_NTWC on X (verbatim raw t.co)",
      "type": "official-archive",
      "dateAccessed": "2026-07-18"
    }
  ],
  "confidence": "high",
  "tags": [
    "earthquake",
    "tsunami",
    "public-masters",
    "california",
    "mendocino-triple-junction",
    "cascadia",
    "shelter-in-place",
    "false-alarm-cancellation",
    "nws-coordination",
    "north-coast"
  ],
  "dateAdded": "2026-05-14",
  "lastUpdated": "2026-07-19",
  "addedBy": "ingestion"
}