Jendetza zapaldu, gorakada eta biziraupena¶

A lethal crowd crush or surge can develop in minutes at concerts, sports stadiums, religious pilgrimages, nightclubs, and street festivals when too many people are funneled into a confined space or bottleneck. Recognizing rising crowd density early, adopting a protective boxer stance to guard your ribcage, and moving diagonally with the crowd flow toward the perimeter are the keys to surviving a crowd surge.

Egin hau orain¶

If you are inside a dense crowd and feel people pressing tightly against your body from multiple directions:

1. Leave immediately at the first sign of uncomfortable pressure: If your shoulders and torso are brushing against people on all four sides and you cannot move your arms freely, do not wait for the concert to start or the bottleneck to clear. Turn and work your way sideways toward the outer edges immediately before density exceeds 5 people per square meter (10.7 square feet).
2. Stay on your feet at all costs: Keep your knees slightly bent and your feet shoulder-width apart, staggered with one foot slightly forward, to lower your center of gravity. Never bend down to pick up a dropped phone, shoe, or bag, because the lateral pressure of bodies in a dense crowd will prevent you from standing back up.
3. Adopt the boxer stance to protect your breathing space: Raise both arms in front of your chest like a boxer, folding your forearms horizontally across your ribs and holding your elbows slightly out 10 to 15 centimeters (4 to 6 inches) in front of your torso. This rigid skeletal frame preserves a pocket of space so your ribcage and diaphragm can expand to take in air.
4. Move diagonally with the flow of the surge, never against it: When a shockwave ripples through a packed crowd, it exerts thousands of Newtons of hydraulic-like force. Do not brace rigidly or push backward against the wave; take small steps with the surge to keep your balance, then step diagonally at a 45-degree angle toward the left or right perimeter during the brief lull between waves.
5. Conserve oxygen and do not scream: Screaming expels the residual air inside your lungs, makes it harder to re-expand your chest under compression, and triggers contagious panic. Breathe slowly and deliberately through your nose or pursed lips whenever the pressure briefly relaxes between surges.
6. If you are knocked down, curl into a tight side-fetal ball immediately: If you fall and cannot get right back up, never lie flat on your back or stomach where weight on your chest will suffocate you. Roll onto your side immediately, pull your knees tightly up to your chest to protect your abdominal organs, and clasp your hands over your head and neck while keeping your forearms braced in front of your face and ribs.

flowchart TD
    Start["Entering or Standing in a Dense Crowd"] --> Density{"1. Can You Move Freely Without Touching All Sides?"}
    Density -->|Yes: Under 4 People per Sq Meter| Watch["Locate Two Exits, Avoid Dead-End Barriers and Stairwell Bottlenecks"]
    Density -->|No: 5+ People per Sq Meter| Boxer["2. Adopt Boxer Stance: Arms Up Creating 10 to 15 cm Chest Space"]
    Boxer --> Surge["3. Move With the Wave to Stay Upright: Never Bend Down for Dropped Items"]
    Surge --> Diagonal["4. Step Diagonally at 45 Degrees Between Waves Toward Outer Perimeter"]
    Diagonal --> FallCheck{"5. Did You Lose Your Footing and Fall?"}
    FallCheck -->|No: Still Standing| Escape["Reach Perimeter Fence, Side Aisle, or Stage Security Barrier"]
    FallCheck -->|Yes: Knocked to Ground| Fetal["Curl Tightly on Your Side in Fetal Position: Protect Chest and Head"]

Understanding crowd density thresholds and fluid dynamics¶

Crowd safety scientists, including researchers Referenced by the United Kingdom Health and Safety Executive (HSE) in The Event Safety Guide (HSG195) and the National Fire Protection Association (NFPA 101 Life Safety Code in the United States), classify crowd risk by counting the number of people standing within 1 square meter (10.76 square feet), an area roughly the size of a standard home shower stall. Once density passes 5 people per square meter (10.76 square feet), a crowd stops behaving like a group of independent individuals and begins obeying the laws of pressurized fluid dynamics.

How laminar flow degrades into stop-and-go waves and crowd turbulence¶

In pedestrian engineering, crowd movement transitions through three distinct physical regimes as density increases:

1. Emari laminarra (leuna): metro karratuko (10,76 oin koadroko 3 pertsona baino gutxiagoko dentsitateetan), oinezkoak oztopoen inguruan leunki ibiltzen dira eta beren abiadura bere borondatez doitzen dute. Pertsona bat gelditzen bada, besteek inguratzen dute bultzadarik transferitu gabe.
2. Stop-and-go olatuak: 4 eta 5 pertsona artean metro karratuko (10,76 oin koadro), korridore edo tunel batean zehar aurrera egiten duen mugimendua luzetarako konpresio-uhinetan deskonposatzen da. Atzean daudenek aurrera jarraitzen dute lerroaren aurrealdea gelditu dela konturatu baino lehen, jendetzaren erdia akordeoi baten antzera konprimituz.
3. Jendetza turbulentzia (jendetzaren lurrikara): 6 pertsonatik gora metro koadroko (10,76 oin koadro), espazio fisikoa erabat desagertzen da. Bultzada edo estropezu txiki bakoitza hezur eta gihar solidoen bidez zuzenean transmititzen da enborra batetik bestera. Bulkadak norabide anitzetatik aldi berean iristen direnez, interferentzia eraikitzaileak bat-bateko uhin bortitzak sortzen ditu, eta 3 eta 5 metrora (10 eta 16 oin) alboetara botatzen dituzte pertsona taldeak euren borondatearen aurka. Jendearen inor izutzen edo oldarkorki jokatzen ez bada ere, trinkoki jositako giza gorputzen fisika hutsak presio-uhin hilgarriak sortzen ditu.

Jendetza zapaltzeak zergatik diren hilgarriak: asfixia konpresiboa eta kolapsoa¶

Albisteek "estampede" hitza erabiltzen dute maiz, eta horrek esan nahi du biktimak oinetan zapaltzen dituela izu itsuan korrika dabilen jendetza batek. Mundu osoko estadio, kontzertu, diskoteka eta erromerietako hondamendi handien inguruko ikerketa forentseek frogatzen dute arraroak direla korrika egitea. Horren ordez, hiru prozesu mekanikoek ia heriotza eta zauritu larriak eragiten dituzte dentsitate handiko jendetzetan.

1. Asfixia konpresiboa (traumatikoa).¶

Airea arnasteko, kostalde arteko muskuluek saihets-kaxa kanporantz zabaldu behar dute eta diafragmak beherantz bultzatu behar du sabeleko barrunbean. Jendetza-indarrak bularraren, bizkarraren eta hegalen kontra presionatzen dituenean 3.000 eta 4.500 Newton baino gehiagoko presio metatuekin (306 eta 459 kilogramoren baliokidea edo 675 eta 1.010 libra arteko karga estatikoen baliokidea), zure bularra apur bat txikiagoa estutzen da arnasten duzun bakoitzean.

Giza arnas-muskuluek 250 eta 400 Newton inguru (25 eta 40 kilogramo edo 55 eta 90 libra) kanporako hedapen-indarra soilik sor ditzaketelako, ezin duzu atzera bota zure aurka makurtuta dauden bost edo sei pertsonen pisuaren aurka. Arnasa ateratzen duen bakoitzean, birikak bolumen txikiago batera jaisten dira, harik eta ezin duzun arte. Bularreko konpresio larriaren 4 eta 6 minuturen buruan, zutik dagoen pertsona batek konortea galtzen du garun-hipoxiagatik eta asfixiako bihotz-geldialdi batean sartzen da oinetan zutik dagoen bitartean. Klinikoki, asfixia konpresiboaren biktimek maskara ekkimotikoa (aurpegiaren, lepoaren eta goiko bularraren kolore gorri iluna) eta hemorragia azpikonjuntibala (odol-hodiak lehertu begien zurietan) atzerantz venoso-presioaren ondorioz, bularra estututa dagoen bitartean glotisa estutzen denean.

2. Zain kaba konpresioa eta zirkulazio shock ortostatikoa¶

Erabateko itoa gertatu baino lehen ere, aurrealdetik atzeko presio biziak sabelaldea eta toraxak beheko kaba bena konprimitzen du, beheko gorputzetik odol desoxigenatua bihotzaren eskuineko aurikulara itzultzen duen horma meheko bena handia. Zain-itzulera bat-batean jaisten denean, bihotz-irteera jaisten da eta garunerako odol-presioa jaisten da. Biktimak shock ortostatiko eta oztopatzaileen ondorioz ahuldu daitezke 60 segundo baino gutxiagoan, eta haien azpian lekuren bat baldin badago inguruko oinezkoen oinen azpian herrenka joan eta lerratzen dira.

3. Jendetzaren kolapso progresiboa (domino pilaketa)¶

Metro koadroko (10,76 oin koadroko 7 eta 9 pertsona arteko dentsitatean), gizabanakoak ez dira jada euren oinen gainean zutik; angelu pikoetan eusten dituzte haien kontra sakatuta dauden gorputzek. Pertsona bakar batek zinta irregular baten, eskailera baten, kable-arrapal baten edo erortzen den botila baten gainean ibiltzen bada, bat-batean hutsune bat irekiko da jendetzaren artean.

Eroritako pertsona horren aurka zuzenean makurtuta dauden pertsonek laguntza fisikoa galtzen dute berehala eta haien gainean hutsunera abiatzen dira. 5 eta 10 segundoren buruan, kolapso lokalizatu bat kanpora hedatzen da zirkulu batean, eta 1,5 eta 2 metro bitarteko (5 eta 6,5 ​​oin) altuera eta bost eta zortzi lagun arteko sakonera duten gorputz pila bat sortuz. Pileup-aren behealdean daudenek berehalako konpresio-asfixia jasaten dute haien gainetik ehunka kilogramoko pisuagatik, bizirik irauten dutenek, hankak edo pelbisak 15 eta 60 minutu baino gehiago giltzapean mantentzen dituzten bitartean, bizitza arriskuan jartzen dute. birrintzeko lesioa eta konpartimendu sindromea.

Gertaera aurreko egoeraren kontzientzia eta tokiko arriskuen ezagupena¶

Jendearen zapalkuntzatik bizirauteko modurik seguruena harrapatuta geratu aurretik egiturazko botilak eta dentsitate-adierazle goiztiarrak antzematea da. Estadio, kontzertu-areto, lurpeko garraio geltoki, jai-leku edo kale-bilketa batera sartzen zaren bakoitzean, hartu 60 segundo zure ingurunea ebaluatzeko.

Saihesteko arrisku handiko tranpa arkitektonikoak¶

• Front-of-stage festival barriers without sector pens: Open-field general admission areas where tens of thousands of fans can push continuously forward toward a single curved stage barrier allow forces from the back of the field to accumulate at the very front. Safer modern venues use segmented crowd pens (such as double-D barriers checked under UK HSE event guidelines) that divide the crowd into isolated compartments with wide lateral escape corridors.
• Downward-sloping ramps and narrow tunnels: Underpasses, stadium vomitories, and sloped streets amplify gravitational force. If a crowd surges while walking down a gradient of even 5 to 10 degrees, a single stumble at the bottom triggers an unstoppable avalanche of falling bodies from above.
• Markatu gabeko urratsak eta bat-bateko kota aldaketak: argi gutxiko korridore baten barruan ezkutatuta dagoen 15 zentimetroko (6 hazbeteko) zinta edo hiru pausoko trantsizio bat ere hilgarri bihurtzen da ibilaldi hilgarrian jendea hain estu bilduta dagoenean, oinetara begiratu ezin dutenean.
• Dead-end alcoves, inward-opening doors, and locked gates: Never allow yourself to be pushed into a recessed doorway, a corner between two solid walls, or against a closed exit gate where pressure has nowhere to dissipate.
• Two-way bidirectional choke points: Bridges, narrow alleys, or festival walkways where an entering crowd collides head-on with an exiting crowd can jump from 3 people per square meter to 8 people per square meter in less than two minutes because neither stream can advance.

Early sensory warning signs of an impending crush¶

Leave the area immediately and move to open space if you notice any of the following warning signs:

1. Loss of foot visibility: You can no longer see the ground or your own shoes because bodies are pressed continuously against your chest and thighs.
2. Involuntary swaying: Your torso sways left, right, or forward in unison with the people around you even when you are trying to stand still.
3. Thermal spike and steam: The air at head height suddenly feels 5 to 10 degrees Celsius (9 to 18 degrees Fahrenheit) hotter, stiflingly humid, and depleted of fresh air, sometimes accompanied by visible condensation rising off the crowd in cool weather.
4. Silence or muffled distress: Contrary to movie depictions of loud screaming, a crowd reaching lethal compression often grows eerily quiet at the epicenter because people do not have enough lung volume to shout, replaced by muffled groans and short gasps for air.
5. Shoes and clothing disappearing underfoot: You feel soft objects such as lost sneakers, bags, and jackets accumulating on the pavement beneath your soles.

Pausoz pauso bizirauteko teknikak jendetzaren gorakada batean¶

Berandu konturatzen bazara metro karratuko (10,76 oin karratuko 6 pertsona edo gehiagotara iristen den jendetzaren barruan harrapatuta zaudela), exekutatu biziraupen teknika biomekaniko hauek zure arnasbidea babesteko eta ateratzeko.

1. Lock in the boxer stance and stagger your footing¶

Your primary mechanical goal in a crowd crush is to keep external forces off your sternum and lower ribs.

• Bring both hands up in front of your collarbones and chin immediately.
• Interlock your fingers or clench your fists firmly, and hold your elbows slightly forward and outward to form a rigid triangular bumper in front of your chest.
• Position one foot 15 to 20 centimeters (6 to 8 inches) ahead of the other, with your knees slightly unlocked. This athletic stance lets you absorb pushes from the front, back, or sides without your heels clipping each other.
• If your shoes have laces and they come untied, leave them untied; never crouch down to tie a shoelace or retrieve a dropped item.

2. Move diagonally like escaping an ocean rip current¶

Just as a swimmer cannot swim straight back to shore against a fast ocean rip current, a pedestrian cannot push straight backward against 500 people surging down a street or toward a stage.

• Wait for the rebound lull: Crowd shockwaves move in rhythmic cycles lasting 5 to 15 seconds, followed by a brief 3-to-5-second relaxation phase as the wave rebounds off a barrier or dissipates.
• Step laterally at 45 degrees during the lull: While the wave is moving, focus 100 percent of your concentration on taking small, shuffling steps in the direction of the wave so your feet stay directly underneath your center of mass. The instant the wave pauses, step diagonally toward the nearest side edge, lateral aisle, or open perimeter.
• Use accordion gaps: Each time a wave recedes, tiny 20-to-30-centimeter (8-to-12-inch) gaps momentarily open between shoulders. Slide sideways into those gaps one step at a time until you reach the outer boundary of the crowd.

3. Seek vertical escape if lateral exits are blocked¶

If you are trapped in a narrow alley, underground station, or fenced courtyard where both sides are sealed by solid walls:

• Look for sturdy elevated structures you can climb up and onto, such as sound and lighting towers, concrete planters, parked vehicles, sturdy tables, scaffolding platforms, or low wall ledges.
• Never allow yourself to be pinned flat between the surging crowd and an unyielding brick wall, glass storefront, or locked iron gate. If you are pushed against a wall, work your way along the wall toward an alcove or climb up onto a raised ledge above waist height where lateral torso compression is lower.

4. Mutual survival: stabilize your immediate neighbors¶

In a dense crowd, your survival is mechanically linked to the people touching your shoulders. If the person directly in front of or beside you falls to the ground, their body creates a void and a tripping obstacle that will pull you down within seconds.

• Communicate calmly in short, three-word phrases with the people pressed against you: "Stay upright together," "Arms up now," "Don't push forward," or "Step left slowly."
• If someone next to you stumbles or begins to faint, hook your elbow under their armpit or grip their upper shoulder immediately to keep them vertical on their feet.
• If people at the back of a bottleneck are pushing forward because they cannot see that the front is blocked or that people have fallen, organize the people around you to chant in unison, "Stop pushing, go back" while raising one hand straight up to visually signal distress to security cameras and spotters on elevated platforms.

Protecting children, older adults, and wheelchair users¶

Vulnerable individuals face disproportionate danger in high-density environments and require proactive positioning before a crowd compresses.

1. Children and infants:
   • Never push a baby stroller or pram into a crowd exceeding 3 people per square meter (10.76 square feet); strollers are easily crushed or tipped over and block pedestrian movement. Use a front-mounted infant carrier only in low-density areas, and exit immediately if people begin pressing close.
   • Lift young children onto your shoulders before density reaches 4 people per square meter so their head and chest remain above the compression zone.
   • Write your mobile phone number with an international dialing code in permanent waterproof marker on your child's forearm before entering any large stadium, festival, or parade, and dress your group in matching neon or high-visibility hats so you can spot each other across a crowd.
2. Wheelchair users and people with mobility aids:
   • Remain inside designated raised accessible viewing platforms that are physically separated from general admission standing areas by structural guardrails and staffed by dedicated security stewards.
   • If a crowd surge approaches an open street or plaza, position a wheelchair behind a massive, immovable buffer such as a wide concrete building pillar, a parked emergency vehicle, or inside an open shop entrance rather than in the main pedestrian flow channel.

Post-escape triage and medical response¶

Birrintzeko gunetik korridore ireki batean, eszena-zuloan edo kalean askatzen zarenean, hartu berehalako neurriak bigarren mailako arriskuetatik urrun egoteko eta biktima larriei laguntzeko.

1. Garbitu irteerako mantala berehala¶

Ez gelditu arnasa hartzeko, telefonoa begiratu edo lagunak besarkatu ihes egin duzun atearen, tunelaren ahoaren edo hesiaren atearen kanpoaldean. Irteera batetik 10 metrora (33 oin) gelditzeak giza presa bat sortzen du, zure atzetik ihes egiten saiatzen ari diren ehunka pertsonak blokeatzen dituena. Ibili gutxienez 30 eta 50 metrora (100 eta 165 oin) botila-lepotik espazio zabal batean gelditu aurretik.

2. Deitu larrialdi-zerbitzuei eta salatu istripu jendetsu bat¶

Deitu zure tokiko larrialdi-zenbakira (911 Estatu Batuetan eta Kanadan, 112 Europar Batasun osoan, 999 Erresuma Batuan edo ikusi gure larrialdi zenbakiak direktorioa). Hitz egin argi eta garbi eta erabili gako-hitz kliniko zehatzak, bidaltzaileek istripu masiboko unitate medikoak ezartzeko, jendetza kontrolatzeko ohiko poliziak baino:

• State the exact sub-location: "We are at the North Tunnel exit of Gate B at [Venue Name], not the main entrance."
• Describe the mechanism: "There is an active crowd crush and pileup. Dozens of people are trapped, unable to breathe, and going into cardiac arrest from asphyxia."
• Request immediate stoppage of the event: Ask police and venue security to halt the music or sporting match, turn on full house lights, and broadcast an announcement instructing the back of the crowd to step backward slowly.

3. Perform CPR with rescue breaths for asphyxial cardiac arrest¶

Victims pulled unresponsive and pulseless from a crowd crush are suffering from hypoxic (asphyxial) cardiac arrest, not sudden electrical heart arrhythmias alone. Their blood and tissues are completely depleted of oxygen.

• Check responsiveness and normal breathing for no more than 10 seconds (ignore occasional gasping or agonal breaths, which are signs of cardiac arrest).
• Start CPR immediately on a firm, flat surface: push hard and fast in the center of the chest at a rate of 100 to 120 compressions per minute and a depth of 5 to 6 centimeters (2 to 2.4 inches) for adults.
• Include rescue breaths if trained: According to resuscitation guidelines from the American Heart Association (United States), the European Resuscitation Council, and the Resuscitation Council UK (United Kingdom), victims of asphyxial arrest (such as drowning or crowd crush) benefit critically from the 30 compressions to 2 rescue breaths cycle to replenish oxygen in the lungs. If you are untrained or unable to give breaths, perform continuous hands-only chest compressions without interruption until paramedics take over.
• If a victim is unconscious but breathing normally, roll them onto their side into the recovery position to keep their airway clear of vomit and monitor their breathing continuously.

4. Monitor survivors for crush syndrome and internal trauma¶

Even if you or a companion walked away from a crowd crush on your own feet, seek immediate hospital evaluation if you experience any of the following symptoms:

• Prolonged limb compression (over 15 minutes): If your legs, hips, or torso were pinned under bodies for more than 15 minutes, damaged muscle cells release potassium, myoglobin, and lactic acid into the bloodstream once pressure is relieved. This condition, known as rhabdomyolysis and crush syndrome, can trigger sudden hyperkalemic cardiac arrest or acute kidney failure hours after rescue (see our crush injury and compartment syndrome guide).
• Shortness of breath, coughing up blood, or sharp chest pain: Severe thoracic compression can cause multiple rib fractures, a collapsed lung (pneumothorax), pulmonary contusions (bruised lungs), or cardiac contusion.
• Facial pinpoint red spots (petechiae), bloodshot eyes, or visual changes: Tiny burst capillaries across the face, neck, and eyes indicate that your upper body experienced severe venous hypertension from traumatic asphyxia and requires a full neurological and respiratory check.
• Severe abdominal pain or dizziness: Blunt compression of the abdomen can rupture the spleen or liver, leading to concealed internal bleeding.

Recommended first aid training¶

Because survival in a crowd crush depends on rapid recognition of asphyxial cardiac arrest and immediate resuscitation, consider taking a certified, hands-on CPR and first aid course through your national Red Cross or Red Crescent society, St John Ambulance (in the United Kingdom, Australia, New Zealand, and Canada), the American Heart Association (in the United States), or a local accredited emergency medical training provider.

Maiz egiten diren galderak¶

Iturriak egiaztatu¶

• United Kingdom Health and Safety Executive (HSE, United Kingdom): The Event Safety Guide: A Guide to Health, Safety and Welfare at Music and Similar Events (HSG195 / The Purple Guide) and Managing Crowds Safely (HSG154) on pedestrian flow rates, barrier design, and crowd density thresholds.
• Sports Grounds Safety Authority (SGSA, United Kingdom): Guide to Safety at Sports Grounds (The Green Guide) on standing terrace capacities, vomitory exit calculations, and progressive crowd collapse prevention.
• National Fire Protection Association (NFPA, United States): NFPA 101: Life Safety Code and NFPA 102: Standard for Grandstands, Folding and Telescopic Seating, Tents, and Membrane Structures on occupant load factors and means of egress widths.
• World Health Organization (WHO, International): Public Health for Mass Gatherings: Key Considerations on mass-casualty preparedness, crowd crush epidemiology, and emergency medical triage at large events.
• American Heart Association (AHA, United States) and European Resuscitation Council (ERC, Europe): Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care on managing asphyxial cardiac arrest and traumatic resuscitation.
• Federal Emergency Management Agency (FEMA, United States): Special Events Contingency Planning for Public Safety Agencies on bottleneck mitigation and crowd management.

Erlazionatutako gidak¶

• Crush injury and compartment syndrome first aid
• CPR and AED step-by-step guide
• Active shooter and public venue attack survival
• Civil unrest, protests, and tear gas safety
• Larrialdi zenbakiak herrialdeka