diff --git a/orangecontrib/spectroscopy/tests/test_owhyper.py b/orangecontrib/spectroscopy/tests/test_owhyper.py
index 84f0254f5..247c918cd 100644
--- a/orangecontrib/spectroscopy/tests/test_owhyper.py
+++ b/orangecontrib/spectroscopy/tests/test_owhyper.py
@@ -202,6 +202,7 @@ def test_simple(self):
 
     def test_unknown(self):
         self.send_signal("Data", self.whitelight[:10])
+        print(self.whitelight[:10])
         wait_for_image(self.widget)
         levels = self.widget.imageplot.img.levels
         self.send_signal("Data", self.whitelight_unknown[:10])
diff --git a/orangecontrib/spectroscopy/widgets/owspectra.py b/orangecontrib/spectroscopy/widgets/owspectra.py
index ea2e96e17..b1f5a491c 100644
--- a/orangecontrib/spectroscopy/widgets/owspectra.py
+++ b/orangecontrib/spectroscopy/widgets/owspectra.py
@@ -2,12 +2,16 @@
 import sys
 from collections import defaultdict
 import random
+import time
 import warnings
 from xml.sax.saxutils import escape
 
 try:
     import dask
     import dask.array as da
+    import dask.distributed
+    dask_client = dask.distributed.Client(processes=False, n_workers=2,
+                                          threads_per_worker=4, dashboard_address=None)
 except ImportError:
     dask = None
 
@@ -276,7 +280,22 @@ class InterruptException(Exception):
     pass
 
 
-class ShowAverage(QObject, ConcurrentMixin):
+class ClientConcurrentMixin(ConcurrentMixin):
+
+    def start1(self, task, *args, **kwargs):
+        dask_client.cancel()
+        super().start(task, *args, **kwargs)
+
+    def cancel1(self):
+        dask_client.cancel()
+        super().cancel()
+
+    def shutdown1(self):
+        dask_client.canvas()
+        super().shutdown()
+
+
+class ShowAverage(QObject, ClientConcurrentMixin):
 
     shown = pyqtSignal()
 
@@ -304,6 +323,9 @@ def compute_averages(data: Orange.data.Table, color_var, subset_indices,
 
         def progress_interrupt(i: float):
             if state.is_interruption_requested():
+                if future:
+                    future.cancel()
+                print("raising")
                 raise InterruptException
 
         def _split_by_color_value(data, color_var):
@@ -324,7 +346,12 @@ def _split_by_color_value(data, color_var):
 
         results = []
 
+        future = None
+
+        is_dask = dask and isinstance(data.X, dask.array.Array)
+
         dsplit = _split_by_color_value(data, color_var)
+        compute_dask = []
         for colorv, indices in dsplit.items():
             for part in [None, "subset", "selection"]:
                 progress_interrupt(0)
@@ -335,11 +362,11 @@ def _split_by_color_value(data, color_var):
                 elif part == "subset":
                     part_selection = indices & subset_indices
                 if np.any(part_selection):
-                    if dask and isinstance(data.X, da.Array):
+                    if is_dask:
                         subset = data.X[part_selection]
-                        std = da.nanstd(subset, axis=0)
-                        mean = da.nanmean(subset, axis=0)
-                        std, mean = dask.compute(std, mean)
+                        compute_dask.extend([da.nanstd(subset, axis=0),
+                                             da.nanmean(subset, axis=0)])
+                        std, mean = None, None
                     else:
                         std = apply_columns_numpy(data.X,
                                                   lambda x: bottleneck.nanstd(x, axis=0),
@@ -349,7 +376,17 @@ def _split_by_color_value(data, color_var):
                                                    lambda x: bottleneck.nanmean(x, axis=0),
                                                    part_selection,
                                                    callback=progress_interrupt)
-                    results.append((colorv, part, mean, std, part_selection))
+                    results.append([colorv, part, mean, std, part_selection])
+
+        if is_dask:
+            future = dask_client.compute(dask.array.vstack(compute_dask))
+            while not future.done():
+                progress_interrupt(0)
+                time.sleep(0.5)
+            computed = future.result()
+            for i, lr in enumerate(results):
+                lr[2] = computed[i*2]
+                lr[3] = computed[i*2+1]
 
         progress_interrupt(0)
         return results
@@ -388,14 +425,8 @@ def on_done(self, res):
     def on_partial_result(self, result):
         pass
 
-    def on_exception(self, ex: Exception):
-        if isinstance(ex, InterruptException):
-            return
 
-        raise ex
-
-
-class ShowIndividual(QObject, ConcurrentMixin):
+class ShowIndividual(QObject, ClientConcurrentMixin):
 
     shown = pyqtSignal()
 
@@ -418,13 +449,26 @@ def show(self):
 
     @staticmethod
     def compute_curves(x, ys, sampled_indices, state: TaskState):
+        is_dask = dask and isinstance(ys, dask.array.Array)
+
+        future = None
+
         def progress_interrupt(i: float):
             if state.is_interruption_requested():
+                if future:
+                    future.cancel()
                 raise InterruptException
 
         progress_interrupt(0)
-        ys = np.asarray(ys[sampled_indices])
+        ys = ys[sampled_indices]
+        if is_dask:
+            future = dask_client.compute(ys)
+            while not future.done():
+                progress_interrupt(0)
+                time.sleep(0.5)
+            ys = future.result()
         ys[np.isinf(ys)] = np.nan  # remove infs that could ruin display
+
         progress_interrupt(0)
         return x, ys, sampled_indices
 
@@ -475,12 +519,6 @@ def on_done(self, res):
     def on_partial_result(self, result):
         pass
 
-    def on_exception(self, ex: Exception):
-        if isinstance(ex, InterruptException):
-            return
-
-        raise ex
-
 
 class InteractiveViewBox(ViewBox):
     def __init__(self, graph):
@@ -1848,5 +1886,6 @@ def migrate_context(cls, context, version):
 if __name__ == "__main__":  # pragma: no cover
     from Orange.widgets.utils.widgetpreview import WidgetPreview
     collagen = Orange.data.Table("collagen.csv")
+    collagen = Orange.data.Table("/home/marko/dask-ssd/brc961-br1001-orange.hdf5")
     WidgetPreview(OWSpectra).run(set_data=collagen,
-                                 set_subset=collagen[:40])
+                                 set_subset=collagen[::2])