Severe Weather Watcher Handbook

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Tornadoes and funnel clouds

Any tornado or funnel cloud should be reported immediately. This includes evidence of tornado debris cloud even if no funnel is visible. Also, clear signs of rotation or other cloud features that would suggest the risk of tornadoes should be reported.Remember, a storm need not be tornadic to pose significant risks (so be on the lookout for risks from straight-line winds, hail and flooding, too).

A detailed discussion of tornado/funnel cloud features is given on page 33. To test your sightings, also refer to page 37 for examples of "false funnels", or tornado look-alikes.

A roaring sound near or under a severe storm should be reported because it may be caused by churning debris from a nearby tornado that you cannot see clearly. A softer, steady roaring or thundering sound can be produced by large hailstones colliding in mid-air nearby, and this, too, should be reported.

Other situations to report

Any weather event that poses a hazard to life or property should be reported,even if not associated with thunderstorms or summer weather. A few examples might be freezing rain,dense fog, widespread strong wind causing damage, blizzards or snowqualls, and extreme snowfall amounts. For snow and fog, the pertinent factor is the occurrence of near-zero visibility.

Waterspouts, large dust devils, or other unusual phenomena also warrant mentioning. Test your sightings of strange clouds and sky conditions around storms against the likely causes and features discussed in the What to watch for section on page 13.

A quick reference table of what and how you should report is given on the outside back cover.

Reporting procedures

The two essentials of any report are speed and accuracy. Every minute saved is a minute applied to releasing a new or updated warning. The danger may have already passed your area but others down the road are still awaiting its arrival.

Precise and thorough descriptions and measurements are also important. Whenever possible, give exact figures for damage, e.g., the diameter of a snapped tree limb or trunk. Measure large hailstones with a ruler. Heavy rain can be measured from the water depth in a can put out in the open.

Even after a severe event has long passed, your discoveries of damage while driving around or talking with neighbours are invaluable for verifying the occurrence. You may run into someone who witnessed a tornado but isn't part of this program or come across signs of damage in a remote rural area, and this information will help the weather office complete its records.

Let us know what you see

As a weather watcher you are the eyes and ears of MSC, helping us to track and confirm what is happening on the ground on days when there is a potential for severe weather.

Most storms are not tornadic, but they may still pose significant risks to public safety. We would like to hear from you when you can supply us with details which help us ascertain the degree of risk to the public.Your observations of the following storm features are particularly helpful:

• lowerings and wall cloud development
• features associated with strong outflow - shelf cloud, roll cloud, blowing dust
• microburst features - rain foot, dust foot or dust plumes
• clear supercell indicators - persistent overshooting top, curved cloud striations (mesocyclone),etc.

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