Data current as of 2026-10-16 · Sourced from NOAA Storm Events
Over the past five years, the National Oceanic and Atmospheric Administration has recorded 5 hail storms within 25 miles of Altadena, CA. Of those, 4 produced hail at least quarter-size — the threshold most insurance carriers consider potentially damaging to asphalt shingles. The largest reported hail in this window was quarter-sized or larger, which can fracture shingle mat and dent metal flashing on contact. 2024 was the most active year on record locally, with 5 documented hail events.
Check Hail History for a Specific Address in Altadena| Severity | Count | What it means for roofs |
|---|---|---|
| Significant | 4 events | Quarter-size, the standard insurance damage threshold |
| Moderate | 1 event | Marble-size, possible cosmetic damage |
| Year | Reported Hail Events Within 25 mi |
|---|---|
| 2024 | 5 events |
2024 was the busiest hail year on record locally for Altadena, with 5 documented events inside the 25-mile radius. Storm activity in Altadena typically peaks in spring and early summer, when the jet stream pushes Gulf moisture into the area and supercell thunderstorms become more frequent.
| Date | Location | Severity | Size | NOAA Comments |
|---|---|---|---|---|
| 2024-03-24 | EL SERENO, CA | Moderate | 0.88" | A strong thunderstorm generate hail with a diameter of 0.88 inches in the city of Alhambra. |
| 2024-03-24 | AZUSA, CA | Significant | 1.00" | A strong thunderstorm generate one inch diameter hail in the city of Azusa. |
| 2024-03-15 | WHITTIER JCT, CA | Significant | 1.00" | A trained spotter reported large hail in the city of Pico Rivera. A thunderstorm generated one inch diameter hail. |
| 2024-03-15 | PICO, CA | Significant | 1.00" | A trained spotter reported large hail in the city of South El Monte. A thunderstorm generated one inch diameter hail. |
| 2024-03-07 | GRANADA HILLS, CA | Significant | 1.00" | In the Porter Ranch area, a strong thunderstorm generated hail of one inch diameter. |
NOAA has recorded 29 high-wind events within 25 miles of Altadena, CA in the past five years. Of those, 29 reached severe-thunderstorm thresholds (58+ mph). The highest measured gust was 78 mph.
| Severity | Count |
|---|---|
| Severe | 12 events |
| Significant | 17 events |
| Date | Location | Gust (mph) | Severity | NOAA Comments |
|---|---|---|---|---|
| 2026-02-18 | BUENA PARK, CA | 58 | Significant | Viewers reported to fox 11 tree damage in Fullerton. Wind gusts in the vicinity at the time were as high as 57 mph at F0063. |
| 2026-02-18 | LANG, CA | 70 | Severe | Strong thunderstorm winds, gusting to 70 MPH, were reported at the Magic Mountain Truck Trail sensor. |
| 2026-02-18 | SYLMAR, CA | 70 | Severe | Strong thunderstorm winds, gusting to 70 MPH, were reported at the Sombrero Road sensor. |
| 2026-02-18 | (MWS)MT WILSON, CA | 78 | Severe | Strong thunderstorm winds, gusting to 78 MPH, were reported at the Barley Flats Road sensor. |
| 2026-02-18 | LA CANADA, CA | 67 | Severe | Strong thunderstorm winds, gusting to 67 MPH, were reported at the Clear Creek RAWS. |
| 2026-02-16 | RESEDA, CA | 60 | Significant | Strong thunderstorm winds knocked down several trees in the community of Reseda. |
| 2026-02-16 | PALMS, CA | 60 | Significant | Strong thunderstorm winds knocked down several trees in the 3600 block of Vinton Avenue in the community of Culver City. |
| 2026-02-16 | LOS ANGELES, CA | 60 | Significant | Strong thunderstorm winds knocked down several trees in the South Los Angeles area. |
| 2026-02-16 | SAN FERNANDO, CA | 60 | Significant | Strong thunderstorm winds knocked down several trees in the San Fernando area. |
| 2026-02-16 | (SMO)SANTA MONICA AR, CA | 60 | Significant | Strong thunderstorm winds knocked down a large tree near the 11200 block of Westminster Avenue in Culver City. |
| 2026-02-16 | HOLLYWOOD, CA | 60 | Significant | Strong thunderstorm winds knocked down several trees in the Hollywood area. |
| 2025-10-14 | (MWS)MT WILSON, CA | 69 | Severe | The Barley Flats sensor reported a thunderstorm wind gust of 69 MPH. |
| 2025-10-14 | ENCINO, CA | 55 | Significant | Strong thunderstorms generated gusty winds. Numerous trees were blown down across Highway 101 near Balboa Avenue. |
| 2025-10-14 | ENCINO, CA | 55 | Significant | Strong thunderstorms generated gusty winds. A large tree was blown down across Burbank Boulevard. |
| 2025-10-14 | LANG, CA | 64 | Severe | The Magic Mountain Truck Trail sensor reported a thunderstorm wind gust of 65 MPH. |
| 2025-10-14 | LANG, CA | 71 | Severe | The Magic Mountain Truck Trail sensor reported a thunderstorm wind gust of 71 MPH. |
| 2025-10-14 | (MWS)MT WILSON, CA | 61 | Significant | The Chilao RAWS reported a thunderstorm wind gust of 61 MPH. |
| 2025-10-14 | HEWITT, CA | 55 | Significant | Strong thunderstorms generate gusty winds. Numerous trees and branches were blown down across Interstate 5 near Burbank. |
| 2025-02-13 | LANG, CA | 77 | Severe | A thunderstorm wind gust of 77 MPH was reported at Magic Mountain Truck Trail. |
| 2025-02-13 | VINCENT, CA | 69 | Severe | A thunderstorm wind gust of 69 MPH was reported at the Rough Road sensor. |
The most recent quarter-size-or-larger hail storm recorded by NOAA within 25 miles of Altadena was on March 24, 2024. HailCheck refreshes from the NOAA Storm Events database daily, so newer events appear here as they are reported.
Altadena averages roughly 1 reported hail event per year within a 25-mile radius. Significant storms (quarter-size or larger) account for 4 of the 5 events recorded over the last five years.
The largest documented hail near Altadena in the last five years was quarter-sized or larger. Most Altadena-area hail falls in the marble-to-quarter range, with destructive storms (egg-size or larger) appearing roughly once every few years.
Most homeowners insurance policies in CA cover hail damage to roofs, siding, and gutters under the dwelling and other-structures coverage. Coverage typically requires the damage to be tied to a verifiable storm date — which is where the NOAA hail history above (and a HAAG-style test square validation) becomes important for the claim file.
Use the HailCheck address search to enter any street address in or near Altadena. HailCheck returns every NOAA hail event within a configurable radius, along with severity bands, dates, and storm narratives for Pro members.
If your property in or near Altadena took on hail during one of the storms above, the standard process for documenting damage is a 10×10 foot test square inspection. A HAAG-trained reviewer counts impact indicators — granule displacement, mat fractures, and bruising — within the marked square and produces a PASS or FAIL document for the claim file.
HailCheck offers a $99 photo-based HAAG-style test square validation. You submit photos from the field, our reviewer evaluates the impact indicators and cross-references the NOAA storm dates listed above, and a written PASS/FAIL determination is returned within one business day. We do not send anyone to the roof — the validation is built around the photos you submit.
Learn About $99 HAAG-Style ValidationAltadena sits east of the traditional hail alley, where hail events are less frequent than the central plains but tend to be associated with strong squall lines and tropical systems. Local roof systems are less commonly hardened for hail, which can mean even moderate impacts produce claim-worthy damage.