diff --git a/wres-datamodel/src/wres/datamodel/bootstrap/BootstrapPool.java b/wres-datamodel/src/wres/datamodel/bootstrap/BootstrapPool.java
index 158e7fd0d..f1065a6d3 100644
--- a/wres-datamodel/src/wres/datamodel/bootstrap/BootstrapPool.java
+++ b/wres-datamodel/src/wres/datamodel/bootstrap/BootstrapPool.java
@@ -21,7 +21,6 @@
 import wres.datamodel.time.Event;
 import wres.datamodel.time.TimeSeries;
 import wres.datamodel.time.TimeSeriesSlicer;
-import wres.statistics.generated.ReferenceTime;
 
 /**
  * Stores the underlying time-series data within a {@link Pool} in an efficient format for bootstrap resampling.
@@ -166,6 +165,7 @@ private Set<Duration> getOffsetsBetweenConsecutiveSeries( List<List<Event<T>>> s
                 Instant last = series.get( i )
                                      .get( 0 )
                                      .getTime();
+
                 Duration offset = Duration.between( first, last )
                                           .abs();
                 offsets.add( offset );
@@ -315,8 +315,8 @@ private BootstrapPool( Pool<TimeSeries<T>> pool )
         this.pool = pool;
         this.hasForecasts = this.pool.get()
                                      .stream()
-                                     .anyMatch( n -> n.getReferenceTimes()
-                                                      .containsKey( ReferenceTime.ReferenceTimeType.T0 ) );
+                                     .anyMatch( t -> TimeSeriesSlicer.hasForecasts( t.getReferenceTimes()
+                                                                                     .keySet() ) );
     }
 
     /**
diff --git a/wres-datamodel/src/wres/datamodel/bootstrap/StationaryBootstrapResampler.java b/wres-datamodel/src/wres/datamodel/bootstrap/StationaryBootstrapResampler.java
index de5958247..71aec7b57 100644
--- a/wres-datamodel/src/wres/datamodel/bootstrap/StationaryBootstrapResampler.java
+++ b/wres-datamodel/src/wres/datamodel/bootstrap/StationaryBootstrapResampler.java
@@ -392,6 +392,21 @@ private int getFirstSampleFromSeriesThatIsNotFirstSeries( int seriesCount,
             Duration gap = Duration.between( first, second )
                                    .abs();
             sampler = this.q.get( gap );
+
+            if ( Objects.isNull( sampler ) )
+            {
+                throw new IllegalStateException( "When attempting to resample time-series, could not find an "
+                                                 + "appropriate resampler for an offset between time-series of "
+                                                 + gap
+                                                 + ". The last series index was "
+                                                 + lastSeriesIndex
+                                                 + " and had a "
+                                                 + "time of "
+                                                 + first
+                                                 + ". The next series index is: "
+                                                 + nextSeriesIndex
+                                                 + " and has a time of " + second + "." );
+            }
         }
 
         // Choose the next event from a randomly selected series?
@@ -1253,6 +1268,8 @@ private Map<Duration, BinomialDistribution> getTransitionProbabilitiesBetweenSer
                                                                                          long meanBlockSizeInTimesteps,
                                                                                          RandomGenerator random )
     {
+        LOGGER.debug( "Creating resamplers for the following time offsets between time-series: {}.", timeOffsets );
+
         Map<Duration, BinomialDistribution> returnMe = new HashMap<>();
 
         if ( !timeOffsets.isEmpty() )
diff --git a/wres-datamodel/src/wres/datamodel/time/TimeSeriesSlicer.java b/wres-datamodel/src/wres/datamodel/time/TimeSeriesSlicer.java
index 7df4aa168..bd20069c4 100644
--- a/wres-datamodel/src/wres/datamodel/time/TimeSeriesSlicer.java
+++ b/wres-datamodel/src/wres/datamodel/time/TimeSeriesSlicer.java
@@ -1369,6 +1369,22 @@ public static TimeScaleOuter augmentTimeScale( TimeScaleOuter existingTimeScale,
         return newTimeScale;
     }
 
+    /**
+     * Determines whether the supplied set of reference times contains any reference times that are indicative of
+     * forecasts, currently {@link ReferenceTimeType#T0} and {@link ReferenceTimeType#ISSUED_TIME} only.
+     *
+     * @param referenceTimeTypes the set of reference time types, not null
+     * @return whether the reference times contain any types that are indicative of forecast
+     */
+
+    public static boolean hasForecasts( Set<ReferenceTimeType> referenceTimeTypes )
+    {
+        Objects.requireNonNull( referenceTimeTypes );
+
+        return referenceTimeTypes.stream()
+                                 .anyMatch( t -> t == ReferenceTimeType.T0 || t == ReferenceTimeType.ISSUED_TIME );
+    }
+
     /**
      * Returns the time-series data type, defaulting to {@link wres.config.yaml.components.DataType#OBSERVATIONS}.
      *
@@ -1393,8 +1409,7 @@ public static <T> DataType getDataType( TimeSeries<T> timeSeries )
             }
 
             Map<ReferenceTime.ReferenceTimeType, Instant> referenceTimes = timeSeries.getReferenceTimes();
-            if ( referenceTimes.containsKey( ReferenceTime.ReferenceTimeType.T0 )
-                 || referenceTimes.containsKey( ReferenceTime.ReferenceTimeType.ISSUED_TIME ) )
+            if ( TimeSeriesSlicer.hasForecasts( referenceTimes.keySet() ) )
             {
                 return DataType.SINGLE_VALUED_FORECASTS;
             }