Weather
Hail damage to cotton, wheat, orchards and vineyards
Hail shreds leaves, breaks stems and knocks off flowers, fruitlets and fruit within minutes. Young leaves regrow, but lost flowers, fruitlets and grain do not come back. In orchards and vineyards hail also spoils the market quality of the harvest.
Crops: Orchards, Grapes, Cotton, Wheat, Vegetables
When it is dangerous
The most dangerous period is grain fill and ripening: shed grain and knocked-off fruit cannot be made up. At flowering hail strips flowers and fruitlets, and in cotton bolls and fruitlets. Hail is most common in foothills and mountain valleys with strong thunderstorms.
Causes
- Convective thunderstorms with hail
- Mountain-valley air circulation that strengthens storms
- A field in the foothills or a mountain valley
Signs on the field
- Shredded leaves and broken stems
- Fruit, bolls and fruitlets knocked to the ground
- Damage in a narrow strip along the storm's path
- Tissue around the wounds ages faster in the following days
How ClusterOS notices it
Satellites see the trace of hail, not the hail itself: Sentinel-2 records a sharp drop in green between two clear images. The image does not name the cause – strong wind, fire or early mowing look the same – so ClusterOS shows the event as a sudden loss of green with the cause not established. The signal is strongest about five days after hail and nearly gone by day fifteen, and clouds after a storm can hide exactly those days. Without weather radar the hail path cannot be located in advance, so the cause is confirmed by an agronomist's visit and your note about what happened.
What to do
- Note what happened and when: hail, storm or mowing
- Photograph the damage – it speeds up the damage assessment and the insurance report
- Visit the field to establish the cause – hail, wind, pests or machinery – and assess the damage
- If needed, register an insurance claim
Questions
Can I get a hail warning in advance?
Only in general terms. A thunderstorm forecast gives a few hours' notice, but without weather radar it cannot show which field the hail will hit. Before the strike the plants are healthy and a satellite has nothing to see, so the main value comes after the event, in assessing the damage.
How do I document hail damage for insurance?
Note what happened and when, and photograph the damage – this speeds up the assessment and the insurance report. An agronomist estimates the share of damaged leaves and other organs. Images from before and after the event show which part of the field lost green.
Learn about this risk on your fields before it becomes a loss
We will show ClusterOS on your own fields: history since 2019, crop stage and all 24 risks.
Other risks in «Weather»
Scientific basis
- Quantifying Hail Damage in Crops Using Sentinel-2 Imagery, Remote Sensing 2022, DOI: 10.3390/rs14040951
- Hail Damage Detection: Integrating Sentinel-2 with Weather Radar, DOI: 10.3390/rs17233850
- MESHS radar model, NHESS, DOI: 10.5194/nhess-24-2541-2024