Measuring hail

One of the goals of NeRAIN is to study hailstorm characteristics; the location, time, size, quantity and hardness of hailstones. In a hailstorm, the size and quantity of hailstones can vary quickly and over very small distances, such as within one mile or even just across the street. We need your help in determining when hail begins, how long it lasts, what size and type of stones, and whether or not rain has accompanied the storm. This is very helpful even if you can only supply a portion of the information.

Even in Nebraska where hail storms are common there will still only be a few hail-producing storms each year. With this in mind you must be ready in advance so the hail doesn't catch you by surprise.
Follow these steps in reporting hailstorm information.

  • Step 1

    If you are at home (or at the site of your reporting station) when a hailstorm hits, note the time that the hail begins as accurately as possible. The times that hail begins and ends are very important pieces of information.

  • Step 2

    Observe the hail storm in progress from a safe and secure location. Please take notes during the storm to help you remember important features from the storm, such as changes in stone size, hardness, and sudden changes in the number of stones reaching the ground. Do not expose yourself to dangerous hailstones. Keep a ruler handy. When a break in the storm gives you the opportunity, measure. Also check to see if the hail is clear, white, hard, soft, smooth, rough or has any other interesting properties. Take note if the hail began before, after, or at the same time the rain began.

  • Step 3

    When the storm has ended, try to approximate the number of stones per unit area (per square foot) on the ground. Since the number is sometimes very large, it may be easier to record the average distance between stones on the ground. If large quantities of hail fell, measure the average depth of accumulated hail on the ground. At the same time, do a quick assessment of hail damage. Most storms do very little damage except to tender plants.

  • Step 4

    Fill out the NeRAIN hail report. If you were not at home, but you experienced hail at another location, a hail report is still beneficial. Make sure to record your actual location accurately so the report is not accidentally associated with your normal station location.

  • Frequently asked hail questions

    1. What if a hail storm occurred, but you were not at home to observe it?

      If this happens, and it will, you will not be able to provide detailed information about the storm. If you can approximate when the storm occurred and some characteristics of the storm, try to do so. When you submit your report, make appropriate remarks expressing your uncertainty. If you do not know the time of occurrence, but you do know the date, that is also useful.
    2. What if you observe a hailstorm from a different location than your station?

      If you are not at home but experience hail storms somewhere else, we welcome these reports as well. Always make sure you note the time and location as accurately as possible.
    3. What if you see some giant hailstones that are more than 2.5 inches in diameter or have very interesting shapes, sizes or other characteristics?

      Every year, giant hailstones fall somewhere in Nebraska. Fortunately, at any specific location they are quite rare. If you see very large or very unusual hailstones, take close-up photographs, collect some samples, preserve them in your freezer, and contact your NeRAIN coordinator. If you see intact hailstones in excess of 5 inches in diameter, quickly and carefully wrap and freeze these stones. These are very rare and will be of great interest to scientists (and the media).