Quick Answer: How Do You Convert Rainfall Depth To Intensity?

What is critical rainfall intensity?

Critical rainfall.

The total amount of rainfall from the time of a distinct increase in rainfall intensity (t0) to the time of the triggering of the first landslide (tf).

Rainfall intensity.

The amount of precipitation in a period, i.e., the rate of precipitation over the considered period..

What is rainfall frequency?

[′rān‚fȯl ‚frē·kwən·sē] (climatology) The number of times, during a specified period of years, that precipitation of a certain magnitude or greater occurs or will occur at a station; numerically, the reciprocal of the frequency is usually given.

What does rainfall in inches mean?

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!

Why is rainfall measured in depth?

The depth is measured because it is not important to know the total amount of rainfall that falls, because an area of indeterminant size is not so much affected by the total amount of water that falls, but the amount of water that falls on an area of given size, which is best represented by the depth of the moisture.

How do you plot a rainfall Hyetograph?

3. HYETOGRAPH  A hyetograph is a graphical representation of the relationship between the rainfall intensity and time.  It is the plot of the rainfall intensity drawn on the ordinate axis against time on the abscissa axis.

What is heavy rainfall?

It is defined as rainfall greater than 100 mm in 24 hours. … In New Zealand, heavy rainfall is relatively common. Often, a significant amount of precipitation occurs in only a few hours, leading to severe flooding and landslide risk.

What is a 1 in 100 year storm event?

A “100 year” storm event has a one in one hundred or 1% chance of happening in any given year. The 100 year flood has a one percent chance of being equalled or exceeded during any given year. … The term “100-year storm” is used to define a rainfall event that statistically has this same 1- percent chance of occurring.

Is 1mm of rain per hour a lot?

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.

How do you calculate total rainfall depth?

Here’s what you’ll need to do:Measure the diameter of the bucket at the level of the rain. … Measure the diameter of the bucket at the bottom in the same way.Calculate the average of the two diameters.Divide by two to find the average radius.Find the average volume of rain = Depth x radius x radius x 3.14.More items…

What is a rainfall return period?

In this report, the term return level refers to the magnitude of the daily rainfall event, and the return period is the frequency of the event. … It is likely that the magnitude of daily rainfall events with a given return period will change by different amounts in each season in the future.

What is another word for raining heavily?

What is another word for raining heavily?sheeting downchucking it downraining hardpeltingtorrentingstreamingbeatinglashingtippingpouring down21 more rows

How do you calculate rainfall deviation?

Meteorologists do this by computing the Coefficient of Variation. The Coefficient Variation is simply the standard deviation divided by the average annual rainfall. For San Francisco’s average rainfall of 21.79″ for its period of record, the standard deviation is 7.63″. Dividing 7.63 by 21.79 gives 0.35.

What does 1 cm rainfall mean?

Measuring rainfall as a depth has become an international standard mainly because it is very easy to convert depth to volume; in fact, the main conversion factor is 1 mm of rainfall = 1 Liter of water/m² (or 0.001 m³ of water/m²); thus, to answer your question, 200cm or rainfall (or 2000 mm) means that every squared …

How do you calculate rainfall intensity?

Rainfall intensities can be accurately measured by means of a continuously recording autographic rain gauge. It is also possible to time the length of individual rainstorms and to calculate the average intensities by dividing the measured rainfall depths by the corresponding duration of the storms.

How do you calculate rainfall per hour?

Search to find the detailed rainfall collections if you want more detailed rainfall intensity data. If all available is monthly average in mm, take the monthly average and divide by number of hours in that month. So if you had 300 mm in April, take 360 mm/(30 days * 24 hours) = 0.5 mm/hour average monthly intensity.

How do you calculate the return period of rainfall?

Determining Return Periods for RainfallLocate the contour lines on either side of your location. … Estimate how far you are between the contours from the lower contour line. … Calculate the difference in rainfall total between the two lines. … Multiply the rainfall difference by the distance you calculated for your location.More items…

Is 1 cm of rain a lot?

Besides, what does 1 cm rain mean? … Moderate rain: Greater than 0.5 mm perhour, but less than 4.0 mm per hour. Heavy rain:Greater than 4 mm per hour, but less than 8 mm perhour. Very heavy rain: Greater than 8 mm per hour.

What is rainfall Hyetograph?

A hyetograph is a graphical representation of the distribution of rainfall intensity over time. … The maximum intensity may not be reached as uniformly as shown in the SCS hyetographs.

Is a plot of cumulative depth of rainfall against time?

 The mass curve of rainfall is a plot of the cumulative depth of rainfall against time, plotted in chronological order.

What are the three types of rainfall?

There are three different types of rainfall:relief.convectional.frontal.

What does 10 cm rainfall mean?

How is the amount of rainfall in a place measured? … Therefore a ‘rain gauge’ is used – the rain water collected in the rain gauge stays there; so that 10mm column of water collected in the gauge means the rain brought enough water to evenly cover the ground in that area with a layer of water 10mm deep.

Does a 100 year storm always cause a 100 year flood?

Does a 100-year storm always cause a 100-year flood? No. Several factors can independently influence the cause-and-effect relation between rainfall and streamflow.

Why is rain bad?

Heavy rain can damage or destroy infrastructure, homes, and businesses. It jeopardizes public health, washing sewage into waterways, kicking up polluting sediments, and creating habitats for disease-carrying insects.