{
  "schemaVersion": 1,
  "label": "Default — USDA FS Forecast Guidance + CMAH",
  "maxProblems": 3,
  "showDangerSuggestion": false,
  "problemTypes": [
    {
      "id": 2,
      "name": "Storm Slab",
      "slab": true,
      "desc": "Release of a cohesive layer of new storm snow, breaking within the storm snow or at the new/old snow interface. Forms during storms.",
      "initiation": [
        "New snowfall within the last 24 hours with potential for ~D1.5 or larger soft slab avalanches in more than just wind-loaded features, or a widespread pattern of small avalanches.",
        "New snow forms a slab through wind effect and/or rapid settlement."
      ],
      "termination": [
        "Likelihood decreases to unlikely.",
        "More than 3 days old on a persistent weak layer, or demonstrated characteristics of Persistent Slab → Persistent Slab."
      ],
      "considerations": [
        "The first storm on a persistent weak layer should be categorized as a Storm Slab unless you expect terrain management considerations associated with Persistent Slabs.",
        "Don’t pair with Wind Slab unless there is a significant difference in distribution, likelihood, and size."
      ],
      "sac": "Storm Slab problems typically last between a few hours and a few days and are commonly distributed widely across terrain that received similar snowfall. During a storm, larger, deeper and sometimes more reactive storm slabs form where wind-drifted snow piles up on leeward terrain; unstable slabs exist in both wind-affected and sheltered areas. Wind slabs are when unstable slabs are limited to wind-loaded areas only. Storm slabs in wind-loaded areas may transition to Wind Slabs as sheltered storm snow stabilizes; over a persistent weak layer they may develop into Persistent Slabs."
    },
    {
      "id": 3,
      "name": "Wind Slab",
      "slab": true,
      "desc": "Release of a cohesive layer of wind-drifted snow, formed in specific, somewhat predictable leeward and cross-loaded terrain.",
      "initiation": [
        "Significant blowing snow within the past ~3 days."
      ],
      "termination": [
        "More than 3 days old and on a persistent weak layer → consider Persistent Slab.",
        "Likelihood decreases to unlikely."
      ],
      "considerations": [
        "Don’t pair with Storm Slab unless there is a significant difference in distribution, likelihood, and size."
      ],
      "sac": "Wind slabs can range from soft to hard, thin to thick, and are often smooth, rounded and sometimes sound hollow. Blowing snow and cracking or collapsing in drifted snow are clear warning signs. Avoid them by sticking to sheltered or wind-scoured areas. Wind slabs over a persistent weak layer may be termed, or develop into, Persistent Slabs."
    },
    {
      "id": 4,
      "name": "Persistent Slab",
      "slab": true,
      "desc": "Release of a cohesive slab when the bond to a buried persistent weak layer (surface hoar, depth hoar, near-surface facets, faceted crusts) breaks.",
      "initiation": [
        "Buried persistent weak layer showing potential for instability.",
        "Existing storm instability on a buried persistent weak layer evolves to more challenging behavior (e.g. remote triggering, wide propagation, unreliable feedback)."
      ],
      "termination": [
        "The problem becomes unreactive.",
        "Average slab increases to ~1.5 m thick, 1F or harder, stubborn to trigger, and capable of high-consequence avalanches (D3+) → consider Deep Persistent Slab."
      ],
      "considerations": [
        "May be initiated with new snow falling on a surface persistent weak layer if you expect terrain management considerations associated with Persistent Slabs."
      ],
      "sac": "Persistent slabs can be triggered long after a storm, released under modest loading, triggered remotely, and propagate widely and unpredictably. Feedback is often irregular, so tracks on a slope are not an indicator of stability. They require a wide margin for error; the most reliable management is conservative terrain choices."
    },
    {
      "id": 5,
      "name": "Deep Persistent Slab",
      "slab": true,
      "desc": "Release of a thick, hard slab when the bond to a persistent weak layer deep in the snowpack or near the ground breaks.",
      "initiation": [
        "Average slab increases to ~1.5 m thick and at least 1F on a persistent weak layer.",
        "Stubborn to triggers.",
        "Capable of producing high-consequence avalanches (D3+)."
      ],
      "termination": [
        "Liquid water production affects the weak layer → Wet Slab.",
        "The problem becomes unreactive.",
        "The problem is significantly less threatening than newly developing avalanche problems."
      ],
      "considerations": [
        "Reserved for low likelihood / high consequence, or high-uncertainty scenarios.",
        "Temporary increases in likelihood are acceptable if the problem is expected to return to low likelihood.",
        "Only pair with Persistent Slab if a newer generation of Persistent Slab requires a significant difference in risk management."
      ],
      "sac": "Hard-to-trigger (low likelihood) but deadly (high consequence) events due to the enormous mass involved. Most commonly triggered from shallow snowpack areas such as rock outcrops or slab margins; typically fail naturally from significant loading, abrupt weather changes or cornice falls. Direct feedback is rare. The most reliable management is avoiding avalanche terrain where the problem exists."
    },
    {
      "id": 7,
      "name": "Wet Slab",
      "slab": true,
      "desc": "Release of a cohesive slab when meltwater or rain weakens the bond to an underlying weak layer or interface.",
      "initiation": [
        "Potential for free water to cause failure at a buried weak layer or interface."
      ],
      "termination": [
        "Free water production or content decreases, or drainage past weak layers is established."
      ],
      "considerations": [
        "Don’t pair with Loose Wet unless there is a significant difference in distribution, likelihood, and size."
      ],
      "sac": "Often occurs during intense or prolonged warming and/or rain-on-snow. Generally more destructive and harder to manage than Wet Loose avalanches; can break widely without clear warning signs. High variability and uncertainty — give yourself a wide safety buffer."
    },
    {
      "id": 6,
      "name": "Wet Loose",
      "slab": false,
      "desc": "Release of unconsolidated damp or wet snow as sun, warming and/or rain weaken the surface.",
      "initiation": [
        "Free water from melt or rain weakens surface snow and can produce more than small and isolated avalanches."
      ],
      "termination": [
        "Liquid water decreases, or snowpack drainage is established.",
        "Activity diminishes to small and isolated to extreme terrain."
      ],
      "considerations": [
        "Don’t pair with Wet Slab unless there is a significant difference in distribution, likelihood, and size."
      ],
      "sac": "Wet loose avalanches entrain heavy snow that is hard to escape and can damage trees, cars and buildings; they can also trigger deeper slabs. Travel when the surface is colder and stronger; rollerballs and pinwheels are obvious precursors."
    },
    {
      "id": 1,
      "name": "Dry Loose",
      "slab": false,
      "desc": "Release of dry, unconsolidated snow that starts at a point and fans out downhill.",
      "initiation": [
        "Weak, dry surface snow with potential for ~D1.5 or larger avalanches or a widespread pattern of small avalanches."
      ],
      "termination": [
        "Loose snow settles into or is buried by a cohesive slab → Storm Slab.",
        "Loose snow wetted and produces sluffs due to warming → Loose Wet.",
        "Activity diminishes to small and isolated to extreme terrain."
      ],
      "considerations": [],
      "sac": "The simplest problem to manage because of predictable behavior and relatively small sizes; most hazardous if you are carried into a terrain trap. Can act as a trigger for slab avalanches."
    },
    {
      "id": 8,
      "name": "Cornice",
      "slab": false,
      "desc": "Release of an overhanging mass of wind-deposited snow from a ridge or summit.",
      "initiation": [
        "Cornice fall cycle expected: large overbuilt cornices with significant blowing snow and/or significant warming or rain.",
        "Cornice fall potential is a controlling factor for avalanche hazard that day."
      ],
      "termination": [
        "Mechanism driving the cycle or increased hazard (blowing snow, warming, rain) has ended.",
        "Newly developing avalanche problems become more threatening."
      ],
      "considerations": [],
      "sac": "Cornices can break suddenly, pull back further than expected onto flat ridgetops, and trigger slabs on the slopes below. Give corniced ridgelines a wide berth and limit exposure below them, especially during warm-ups or rapid wind loading."
    },
    {
      "id": 9,
      "name": "Glide",
      "slab": false,
      "desc": "Release of the entire snow cover gliding over smooth ground (slick bedrock, grassy slopes).",
      "initiation": [
        "Glide cycle indicated or in progress.",
        "Indicators present: warm ground with heavy snowfall, heavy rainfall on an unconsolidated homogenous snowpack, or rapid onset of glide cracks."
      ],
      "termination": [
        "Adequate lag time since the driving mechanism (rainfall, melt at the basal interface, rapid settlement) ended.",
        "Observations indicate the cycle has ended."
      ],
      "considerations": [
        "High uncertainty on timing; consider maintaining as a problem for at least 48 hours after onset of glide avalanches."
      ],
      "sac": "Glide avalanches are unlikely to be triggered by a person, but natural failures are very hard to predict. Safe travel relies on identifying and avoiding the specific slopes where they occur; recently opened glide cracks and recent glide avalanches are significant indicators."
    }
  ],
  "conditions": [
    {
      "id": "new_snow_24h",
      "suggests": [
        2
      ],
      "label": "New snow in the last 24 hours forming a soft slab (~D1.5+ possible) in more than just wind-loaded features"
    },
    {
      "id": "blowing_snow_3d",
      "suggests": [
        3
      ],
      "label": "Significant blowing snow within the past ~3 days"
    },
    {
      "id": "pwl_reactive",
      "suggests": [
        4
      ],
      "label": "A buried persistent weak layer showing potential for instability (remote triggering, wide propagation, unreliable feedback)"
    },
    {
      "id": "slab_on_pwl_3d",
      "suggests": [
        4
      ],
      "label": "A storm or wind slab more than 3 days old sitting on a persistent weak layer"
    },
    {
      "id": "deep_hard_slab",
      "suggests": [
        5
      ],
      "label": "A slab ~1.5 m (5 ft) or thicker, 1F or harder, on a persistent weak layer — stubborn but capable of D3+"
    },
    {
      "id": "dry_surface_weak",
      "suggests": [
        1
      ],
      "label": "Weak, dry surface snow with potential for ~D1.5+ or a widespread pattern of small loose avalanches"
    },
    {
      "id": "surface_free_water",
      "suggests": [
        6
      ],
      "label": "Free water from melt or rain weakening the surface snow"
    },
    {
      "id": "water_to_layer",
      "suggests": [
        7
      ],
      "label": "Potential for free water to reach and fail a buried weak layer or interface"
    },
    {
      "id": "cornice_cycle",
      "suggests": [
        8
      ],
      "label": "Cornice fall cycle expected (large overbuilt cornices plus blowing snow, warming or rain)"
    },
    {
      "id": "glide_cycle",
      "suggests": [
        9
      ],
      "label": "Glide cycle indicated or in progress (heavy snow on warm ground, heavy rain, or rapid onset of glide cracks)"
    },
    {
      "id": "no_hazard",
      "suggests": [],
      "label": "No associated avalanche hazard — structure alone is not a problem (use the Forecast Discussion instead)"
    }
  ],
  "sensitivity": [
    {
      "key": "unreactive",
      "label": "Unreactive",
      "natural": "No avalanches",
      "human": "No avalanches",
      "explosive": "Very large explosives in several locations: no slab",
      "cornice": "No slab from very large cornice fall"
    },
    {
      "key": "stubborn",
      "label": "Stubborn",
      "natural": "Few",
      "human": "Difficult to trigger",
      "explosive": "Large explosives & air blasts, often in several locations: some",
      "cornice": "Large"
    },
    {
      "key": "reactive",
      "label": "Reactive",
      "natural": "Several",
      "human": "Easy to trigger with ski cuts",
      "explosive": "Single hand charge: many",
      "cornice": "Medium"
    },
    {
      "key": "touchy",
      "label": "Touchy",
      "natural": "Numerous",
      "human": "Triggering almost certain",
      "explosive": "Any size: numerous",
      "cornice": "Any size"
    }
  ],
  "distribution": [
    {
      "key": "isolated",
      "label": "Isolated",
      "density": "The avalanche problem is spotty and found in only a few terrain features",
      "evidence": "Evidence is rare and hard to find"
    },
    {
      "key": "specific",
      "label": "Specific",
      "density": "The avalanche problem exists in terrain features with common characteristics",
      "evidence": "Evidence exists but is not always obvious"
    },
    {
      "key": "widespread",
      "label": "Widespread",
      "density": "The avalanche problem is found in many locations and terrain features",
      "evidence": "Evidence is everywhere and easy to find"
    }
  ],
  "likelihoodMatrix": {
    "widespread": {
      "unreactive": 1,
      "stubborn": 2,
      "reactive": 4,
      "touchy": 5
    },
    "specific": {
      "unreactive": 1,
      "stubborn": 2,
      "reactive": 3,
      "touchy": 4
    },
    "isolated": {
      "unreactive": 1,
      "stubborn": 1,
      "reactive": 2,
      "touchy": 3
    }
  },
  "likelihoodLabels": {
    "1": "Unlikely",
    "2": "Possible",
    "3": "Likely",
    "4": "Very Likely",
    "5": "Certain"
  },
  "sizes": [
    {
      "value": 1,
      "label": "D1",
      "word": "Small",
      "desc": "Unlikely to bury a person"
    },
    {
      "value": 1.5,
      "label": "D1.5"
    },
    {
      "value": 2,
      "label": "D2",
      "word": "Large",
      "desc": "Can bury a person"
    },
    {
      "value": 2.5,
      "label": "D2.5"
    },
    {
      "value": 3,
      "label": "D3",
      "word": "Very Large",
      "desc": "Can destroy a house"
    },
    {
      "value": 3.5,
      "label": "D3.5"
    },
    {
      "value": 4,
      "label": "D4–5",
      "word": "Historic",
      "desc": "Can destroy part or all of a village"
    }
  ],
  "dangerLevels": [
    {
      "level": 0,
      "name": "No Rating",
      "color": "#939598",
      "advice": "Information is scarce or the timeline exceeds 24 hours (“No Rating – Information Available”)."
    },
    {
      "level": 1,
      "name": "Low",
      "color": "#50B848",
      "advice": "Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.",
      "likelihood": "Natural and human-triggered avalanches unlikely.",
      "sizeDist": "Small avalanches in isolated areas or extreme terrain."
    },
    {
      "level": 2,
      "name": "Moderate",
      "color": "#FFF200",
      "advice": "Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.",
      "likelihood": "Natural avalanches unlikely; human-triggered avalanches possible.",
      "sizeDist": "Small avalanches in specific areas; or large avalanches in isolated areas."
    },
    {
      "level": 3,
      "name": "Considerable",
      "color": "#F7941E",
      "advice": "Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential.",
      "likelihood": "Natural avalanches possible; human-triggered avalanches likely.",
      "sizeDist": "Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas."
    },
    {
      "level": 4,
      "name": "High",
      "color": "#ED1C24",
      "advice": "Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.",
      "likelihood": "Natural avalanches likely; human-triggered avalanches very likely.",
      "sizeDist": "Large avalanches in many areas; or very large avalanches in specific areas."
    },
    {
      "level": 5,
      "name": "Extreme",
      "color": "#231F20",
      "advice": "Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.",
      "likelihood": "Natural and human-triggered avalanches certain.",
      "sizeDist": "Very large avalanches in many areas."
    }
  ],
  "dangerTable": {
    "1": [
      1,
      1,
      1,
      2
    ],
    "2": [
      1,
      2,
      2,
      3
    ],
    "3": [
      2,
      2,
      3,
      3
    ],
    "4": [
      2,
      3,
      3,
      4
    ],
    "5": [
      3,
      3,
      3,
      5
    ]
  },
  "gradientTable": {
    "1": [
      [
        1
      ],
      [
        1
      ],
      [
        1
      ],
      [
        2
      ]
    ],
    "2": [
      [
        1
      ],
      [
        2
      ],
      [
        2
      ],
      [
        3
      ]
    ],
    "3": [
      [
        2
      ],
      [
        2,
        3
      ],
      [
        3
      ],
      [
        3,
        4
      ]
    ],
    "4": [
      [
        2
      ],
      [
        3,
        4
      ],
      [
        3,
        4
      ],
      [
        4
      ]
    ],
    "5": [
      [
        3,
        2
      ],
      [
        3,
        4
      ],
      [
        3,
        4
      ],
      [
        5
      ]
    ]
  },
  "pairingRules": [
    {
      "a": 2,
      "b": 3,
      "source": "FG Table 1",
      "reason": "Storm slabs form during storms and exist in both exposed and sheltered terrain; wind slabs exist only in wind-loaded terrain. If slabs exist in sheltered and wind-loaded terrain and formed during a storm, use Storm Slab. If they exist only in wind-loaded areas (not enough new snow for slabs in sheltered areas, or old snow redistributed by wind), use Wind Slab. Don’t pair them unless there is a significant difference in distribution, likelihood, and size."
    },
    {
      "a": 6,
      "b": 7,
      "source": "FG Table 1",
      "reason": "Wet Loose and Wet Slab are both wet problems. Don’t pair them unless there is a significant difference in distribution, likelihood, and size."
    },
    {
      "a": 4,
      "b": 5,
      "source": "FG Table 1",
      "reason": "Only pair Deep Persistent Slab with Persistent Slab if a newer generation of Persistent Slab requires a significant difference in risk management."
    },
    {
      "a": 1,
      "b": 6,
      "source": "FG Table 1 (transition)",
      "requireJustification": false,
      "reason": "Dry Loose transitions to Loose Wet when warming wets the surface snow; you would not normally list both unless they are clearly separated (e.g. by aspect or elevation)."
    }
  ],
  "help": {
    "problems": "Each avalanche problem is described by four factors — type, location (aspect & elevation), likelihood, and size — whose combination defines the hazard. Use as few problems as possible to cover the travel advice, and assign a problem only when there is an associated avalanche hazard: do not use problems to describe snowpack structure. — Forecast Guidance §1.2, §3.4",
    "sensitivity": "Sensitivity to triggers: how easily the problem releases — from Unreactive (no natural or human-triggered avalanches) to Touchy (numerous naturals; triggering almost certain). — Forecast Guidance Table 2",
    "distribution": "Spatial distribution: how widely the problem is found and how hard the evidence is to find — Isolated, Specific or Widespread. — Forecast Guidance Table 3",
    "likelihood": "Likelihood is the chance of a human triggering an avalanche, driven by sensitivity and distribution (Figure 2). The tool reads it from that matrix; widen a range to express uncertainty. — Forecast Guidance §1.2.2, §3.4",
    "size": "Use the D-scale. Keep the range of sizes to two or less and describe outliers in the problem description. — Forecast Guidance Table 4, §3.4",
    "location": "Show the aspects and elevations where the problem is most likely to be encountered; describe nuances in the problem description. — Forecast Guidance §3.4",
    "hazardChart": "Each problem is plotted by likelihood (vertical) and destructive size (horizontal); toward the upper right means greater hazard. — Statham et al. (2018) Fig 3",
    "danger": "Danger ratings are assigned from the appropriate travel advice for the day’s combination of problems. When criteria conflict or sit on the line between two levels, decide primarily by the Travel Advice. This suggestion is a consistency aid only — you set the rating. — Forecast Guidance §2.1–2.2"
  },
  "onTheLine": [
    {
      "title": "Low vs Moderate — triggering unlikely, but poor structure persists",
      "text": "Assign LOW if people can generally travel in start zones, tracks and runouts without significant avalanche risk (e.g. 7+ days without avalanches, precipitation or significant wind, with unreactive tests). Assign MODERATE if poor structure persists and you are concerned about a lingering risk of triggering (e.g. limited observations and low traffic)."
    },
    {
      "title": "Moderate vs Considerable — Persistent Slab likelihood decreasing",
      "text": "When triggering a D2.5+ avalanche decreases from likely to possible and naturals are unlikely, CONSIDERABLE is appropriate: the larger size and consequences should shape travelers’ mindset and terrain choices."
    },
    {
      "title": "Moderate vs Considerable — loose snow cycles",
      "text": "Base it on the most likely size: CONSIDERABLE if most avalanches are expected to be D2+; MODERATE if most are expected to be D1."
    },
    {
      "title": "Considerable vs High — naturals possible, human triggering very likely",
      "text": "Assign HIGH if travel in avalanche terrain is not recommended."
    },
    {
      "title": "High vs Extreme",
      "text": "Assign EXTREME if advising people to avoid all avalanche terrain (including areas typically safe during HIGH), or if you anticipate widespread D3 and potential for multiple D4 avalanches. Consider EXTREME if an incoming storm will raise danger from LOW to HIGH over widespread buried weak layers."
    },
    {
      "title": "Temporal",
      "text": "If danger peaks during daylight, issue the higher rating and explain the rise in the text. Consider the higher rating if it peaks near sundown, especially with uncertain timing. If it peaks well after dark, issue the lower rating and explain the overnight rise."
    },
    {
      "title": "Spatial",
      "text": "Usually assign the higher rating and explain spatial patterns in the problem discussion (e.g. a heavily used pass that is more dangerous). Consider the lower rating, elaborated in the Bottom Line, if the higher danger exists only in small areas of remote terrain."
    }
  ],
  "writing": {
    "overview": [
      "Put important information first — users may spend only 10 seconds.",
      "Keep it simple and short.",
      "Avoid jargon or define it.",
      "Avoid passive voice."
    ],
    "travelAdvice": [
      "Keep travel advice consistent across the Bottom Line, Danger and Problem sections.",
      "Highlight generally safer terrain and terrain or timing strategies that reduce risk.",
      "At LOW, do not tell people there is no chance of avalanches.",
      "At MODERATE or CONSIDERABLE, describe the hazard, where it is, and travel techniques that reduce risk.",
      "At HIGH or EXTREME it is acceptable to tell people to stay out of avalanche terrain."
    ],
    "bottomLine": [
      "Aim for three sentences or fewer.",
      "Answer: What is it? Where is it? What can readers do about it?",
      "Focus on the 1 or 2 key points.",
      "Do not simply repeat the NAPADS travel advice; give specific advice (slope type, exposure to steep slopes above).",
      "Avoid jargon — “wind drifts”, not “wind slabs”; “sugary snow”, not “facets”."
    ],
    "problemDescription": [
      "Answer what / where / what to do with more resolution than the Bottom Line.",
      "Include recent avalanches, expected natural activity and sensitivity, remote triggering, slab character, thickness and width, timing, and where danger is elevated."
    ],
    "discussion": [
      "Optional — skip it when problem statements suffice.",
      "Use it when there are no problems, to highlight key observations, uncertainty (always explain why), differences within the zone, nuance, or decision-making."
    ]
  },
  "bandLabels": {
    "upper": "Above Treeline",
    "middle": "Near Treeline",
    "lower": "Below Treeline"
  }
}