/**
 * Fire weather utility functions for interpreting fire danger indices
 */
/**
 * Haines Index category information
 * The Haines Index measures atmospheric stability and dryness that affect fire growth potential
 * Scale: 2-6 (Low, Moderate, High fire growth potential)
 */
export interface HainesCategory {
    level: string;
    description: string;
    fireGrowthPotential: string;
    color: string;
}
/**
 * Get Haines Index category
 * Haines Index: 2-6 scale measuring atmospheric contribution to fire growth
 * - Low elevation (< 3,000 ft): 2-3 = Low, 4 = Moderate, 5-6 = High
 * - Mid elevation (3,000-10,000 ft): Same scale
 * - High elevation (> 10,000 ft): Same scale
 *
 * The ladder is contiguous (`<= 3` / `<= 4` / `<= 5` / else) so a non-integer
 * value bands into the rung it falls within rather than falling through to
 * the top rung.
 */
export declare function getHainesCategory(hainesValue: number): HainesCategory;
/**
 * Get grassland fire danger category
 * Scale: 1-4 (Low, Moderate, High, Very High)
 *
 * The ladder is contiguous (`<= 1` / `<= 2` / `<= 3` / else) so a non-integer
 * value bands into the rung it falls within rather than falling through to
 * the top rung.
 */
export declare function getGrasslandFireDangerCategory(value: number): {
    level: string;
    description: string;
    color: string;
};
/**
 * Get red flag threat index category
 * Indicates potential for Red Flag Warning conditions
 */
export declare function getRedFlagCategory(value: number): {
    level: string;
    description: string;
    color: string;
};
/**
 * Get current fire weather value from gridpoint data series
 * Returns the value for the current time period
 */
export declare function getCurrentFireWeatherValue(dataSeries: {
    values: Array<{
        validTime: string;
        value: number;
    }>;
} | undefined): number | null;
/**
 * Format mixing height value
 * Mixing height indicates how high smoke and pollutants can rise
 * Higher is generally better for smoke dispersion
 */
export declare function formatMixingHeight(heightFt: number | null): string;
/**
 * Interpret transport wind speed for fire behavior
 * Transport winds carry smoke and can influence fire spread
 */
export declare function interpretTransportWind(speedMph: number | null): string;
/**
 * Fire weather context information for when indices aren't available
 */
export interface FireWeatherContext {
    hasIndices: boolean;
    reason: string;
    seasonalRisk: 'Low' | 'Moderate' | 'Elevated' | 'High';
    explanatoryText: string;
}
/**
 * Determine fire weather context and why indices may not be available
 * Provides user-friendly explanations for missing fire weather data
 */
export declare function getFireWeatherContext(latitude: number, longitude: number, timestamp: string, hainesValue: number | null, grasslandValue: number | null, redFlagValue: number | null, humidity?: number | null): FireWeatherContext;
/**
 * Calculate the Fosberg Fire Weather Index (FFWI) from surface observations.
 *
 * Reference: Fosberg, M.A. (1978), "Weather in wildland fire management: the
 * fire weather index," as implemented in NWS/WFAS (Wildland Fire Assessment
 * System) documentation. This is the standard surface-inputs formulation:
 *
 * 1. Equilibrium moisture content (EMC, `m`) from relative humidity and
 *    temperature, via a three-branch piecewise fit:
 *    - RH < 10:        m = 0.03229 + 0.281073*RH - 0.000578*RH*T
 *    - 10 <= RH <= 50:  m = 2.22749 + 0.160107*RH - 0.014784*T
 *    - RH > 50:        m = 21.0606 + 0.005565*RH^2 - 0.00035*RH*T - 0.483199*RH
 * 2. Moisture damping coefficient:
 *    eta = 1 - 2*(m/30) + 1.5*(m/30)^2 - 0.5*(m/30)^3, clamped to >= 0.
 * 3. FFWI = eta * sqrt(1 + U^2) / 0.3002, clamped to the published 0-100
 *    range (U is sustained wind speed in mph).
 *
 * This is a pure math transcription with no input range validation — the
 * caller is expected to pass sane meteorological values. Any non-finite
 * input (NaN or +/-Infinity, in tempF, rhPercent, or windMph) returns `NaN`;
 * callers must check `Number.isFinite()` on the result before rendering it
 * and fall back to an "unavailable" message rather than surfacing NaN.
 *
 * @param tempF Temperature in degrees Fahrenheit
 * @param rhPercent Relative humidity as a percentage (0-100 in normal use)
 * @param windMph Sustained wind speed in miles per hour
 * @returns FFWI on a 0-100 scale, or NaN if any input is non-finite
 */
export declare function calculateFosbergIndex(tempF: number, rhPercent: number, windMph: number): number;
/**
 * Get Fosberg Fire Weather Index (FFWI) category.
 *
 * Band boundaries (`< 25` Low, `25-39` Moderate, `40-49` High, `>= 50`
 * Extreme) are a **project heuristic**, not an agency-published scale —
 * published FFWI usage generally treats values >= 50 as significant fire
 * weather, but there is no single universally standardized banding below
 * that threshold. Disclose this derivation to users alongside the number.
 */
export declare function getFosbergCategory(ffwi: number): {
    level: string;
    description: string;
    color: string;
};
/**
 * Describe vapour-pressure deficit (VPD) drying power for a fire-weather
 * dryness-context line.
 *
 * Bands (`< 1` low, `1-2` moderate, `2-3` high, `> 3` extreme kPa) are a
 * **project heuristic** for narrating drying power, not an agency scale.
 */
export declare function describeVpd(kPa: number): string;
/**
 * Describe topsoil (0-1 cm) volumetric moisture content for a fire-weather
 * dryness-context line.
 *
 * Bands (`< 0.1` very dry, `0.1-0.2` dry, `0.2-0.3` moist, `> 0.3` wet
 * m^3/m^3) are a **project heuristic**, not an agency scale.
 */
export declare function describeTopsoilMoisture(m3m3: number): string;
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