The standard instrument for the measurement of rainfall is the 203mm (8 inch) rain gauge . This is essentially a circular funnel with a diameter of 203mm which collects the rain into a graduated and calibrated cylinder. The measuring cylinder can record up to 25mm of precipitation.
How do you calculate rainfall?
Find the average volume of rain = Depth x radius x radius x 3.14 . Find the area at the top of the bucket (this is the area over which the rain is collected). Divide the rainfall volume by this area to get the rainfall.
How rainfall is measured in cm?
The amount of rainfall is expressed as depth in centimeters (or millimeters) which falls on a level surface. Intensity of rainfall is the rate at which it falls at any one time. It is expressed as cm per hour or mm per hour. Rainfall is measured by means of rain gauges.
What does it mean 1 inch of rain?
Rainfall amount is described as the depth of water reaching the ground, typically in inches or millimeters (25 mm equals one inch). An inch of rain is exactly that, water that is one inch deep . One inch of rainfall equals 4.7 gallons of water per square yard or 22,650 gallons of water per acre!
How many cm is heavy rain?
in six minutes; 3) “heavy,” over 0.76 cm (0.30 in.) per hour or more than 0.076 cm (0.03 in.)
Why is snow measured in cm?
In many snow events a ratio of 10 to 1 can be applied to the amount of snow to determine its water equivalent. In other words, 1 centimetre of snow is equivalent to about 1 millimetre of water once the snow is melted .
Is 1 inch rain a lot?
One (1.00) inch of rain – A light moderate rain never reaches this amount , heavy rain for several hours (2-5 hours). There would be deep standing water for long periods of time.
What is a light rain?
Rain and drizzle are the only forms of liquid precipitation. Rain is classified as light, meaning rain falling at a rate between a trace and 0.10 inch per hour ; moderate, 0.11 to 0.30 inch per hour; heavy, more than 0.30 inch per hour.
Is rain measured in cubic inches?
From other sources on the web, the basic idea is that the area of the collection is given in squared units of length( e.g. square inches) and the volume of rain is measured in cubed units of length (e.g. cubic inches). ... So a reading of “1 inch” of rainfall means 1 cubic inch of rain fell per square inch of ground.
Why is rain measured in cm?
But more importantly, why does a unit of length measure something like rainfall? The short answer is rain gauge. ... So when you see a rainfall reading in millimetres or centimetres, it is simply the height to which the collected water rose in the funnel of the rain gauge.
Is 1mm rain heavy?
Heavy (thick) drizzle: Impairs visibility and is measurable in a raingauge, rates up to 1 mm per hour . ... Slight rain: Less than 0.5 mm per hour. Moderate rain: Greater than 0.5 mm per hour, but less than 4.0 mm per hour. Heavy rain: Greater than 4 mm per hour, but less than 8 mm per hour.
Is 1 cm a lot of snow?
A rule of thumb is that 1 mm of water produces 1 cm of snow , but this differs from storm to storm and from location to location.
What does 1 cm snow mean?
Snow is normally measured in “centimetres”. ... In many snow events a ratio of 10 to 1 can be applied to the amount of snow to determine its water equivalent. In other words, 1 centimetre of snow is equivalent to about 1 millimetre of water once the snow is melted .
What instrument is used to measure snow?
A snow gauge is an instrument used by meteorologists and hydrologists to measure the amount of snow precipitation over a set period of time.
Can 1 inch of rain cause flooding?
Floods can happen during heavy rains , when ocean waves come on shore, when snow melts quickly, or when dams or levees break. Damaging flooding may happen with only a few inches of water, or it may cover a house to the rooftop. ... Flash floods occur when heavy rainfall exceeds the ability of the ground to absorb it.
