title: How to subset consecutive rows if they meet a condition
body: <p>I am using R to analyze a number of time series (1951-2013) containing daily values of Max and Min temperatures. The data has the following structure:</p>
  
  <pre><code>YEAR MONTH  DAY     MAX    MIN
  1985     1    1    22.8    9.4
  1985     1    2    28.6   11.7
  1985     1    3    24.7   12.2
  1985     1    4    17.2    8.0
  1985     1    5    17.9    7.6
  1985     1    6    17.7    8.1
  </code></pre>
  
  <p>I need to find the frequency of heat waves based on this definition: A period of three or more consecutive days ‎with a daily maximum and minimum temperature exceeding the 90th percentile of the maximum ‎and minimum temperatures for all days in the studied period.</p>
  
  <p>Basically, I want to subset those consecutive days (three or more) when the Max and Min temp exceed a threshold value. The output would be something like this:</p>
  
  <pre><code>YEAR MONTH   DAY     MAX     MIN
  1989     7    18    45.0    23.5
  1989     7    19    44.2    26.1
  1989     7    20    44.7    24.4
  1989     7    21    44.6    29.5
  1989     7    24    44.4    31.6
  1989     7    25    44.2    26.7
  1989     7    26    44.5    25.0
  1989     7    28    44.8    26.0
  1989     7    29    44.8    24.6
  1989     8    19    45.0    24.3
  1989     8    20    44.8    26.0
  1989     8    21    44.4    24.0
  1989     8    22    45.2    25.0
  </code></pre>
  
  <p>I have tried the following to subset my full dataset to just the days that exceed the 90th percentile temperature:</p>
  
  <pre><code>HW&lt;- subset(Mydata, Mydata$MAX &gt;= (quantile(Mydata$MAX,.9)) &amp;
                      Mydata$MIN &gt;= (quantile(Mydata$MIN,.9)))
  </code></pre>
  
  <p>However, I got stuck in how I can subset only consecutive days that have met the condition.</p>